feat: Phase 2 — Delegated State, Auth, Review-Gate, Notifications, Zombie-Reset

backend/Data/Migrations/20260618214335_AddNotifications.Designer.cs

@@ -0,0 +1,311 @@
+// <auto-generated />
+using System;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+using Nexus.Api.Data;
+using Npgsql.EntityFrameworkCore.PostgreSQL.Metadata;
+
+#nullable disable
+
+namespace Nexus.Api.Migrations
+{
+    [DbContext(typeof(NexusDbContext))]
+    [Migration("20260618214335_AddNotifications")]
+    partial class AddNotifications
+    {
+        /// <inheritdoc />
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder
+                .HasAnnotation("ProductVersion", "10.0.8")
+                .HasAnnotation("Relational:MaxIdentifierLength", 63);
+
+            NpgsqlModelBuilderExtensions.UseIdentityByDefaultColumns(modelBuilder);
+
+            modelBuilder.Entity("Nexus.Api.Data.ActivityEvent", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("bigint");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<long>("Id"));
+
+                    b.Property<DateTimeOffset>("CreatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("Message")
+                        .IsRequired()
+                        .HasMaxLength(1000)
+                        .HasColumnType("character varying(1000)");
+
+                    b.Property<Guid?>("TaskId")
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("Type")
+                        .IsRequired()
+                        .HasColumnType("text");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("CreatedAt");
+
+                    b.HasIndex("TaskId");
+
+                    b.ToTable("Activity");
+                });
+
+            modelBuilder.Entity("Nexus.Api.Data.NexusUser", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<DateTimeOffset>("CreatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("DisplayName")
+                        .IsRequired()
+                        .HasMaxLength(100)
+                        .HasColumnType("character varying(100)");
+
+                    b.Property<string>("Email")
+                        .IsRequired()
+                        .HasMaxLength(120)
+                        .HasColumnType("character varying(120)");
+
+                    b.Property<DateTimeOffset?>("LastLoginAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("NormalizedEmail")
+                        .IsRequired()
+                        .HasMaxLength(120)
+                        .HasColumnType("character varying(120)");
+
+                    b.Property<string>("PasswordHash")
+                        .IsRequired()
+                        .HasColumnType("text");
+
+                    b.Property<string>("Role")
+                        .IsRequired()
+                        .HasColumnType("text");
+
+                    b.Property<DateTimeOffset>("UpdatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("NormalizedEmail")
+                        .IsUnique();
+
+                    b.ToTable("Users");
+                });
+
+            modelBuilder.Entity("Nexus.Api.Data.Notification", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<DateTimeOffset>("CreatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("ForUser")
+                        .IsRequired()
+                        .HasMaxLength(60)
+                        .HasColumnType("character varying(60)");
+
+                    b.Property<bool>("IsRead")
+                        .HasColumnType("boolean");
+
+                    b.Property<string>("Message")
+                        .HasMaxLength(1000)
+                        .HasColumnType("character varying(1000)");
+
+                    b.Property<Guid?>("TaskId")
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("Title")
+                        .IsRequired()
+                        .HasMaxLength(240)
+                        .HasColumnType("character varying(240)");
+
+                    b.Property<string>("Type")
+                        .IsRequired()
+                        .HasMaxLength(60)
+                        .HasColumnType("character varying(60)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("ForUser", "IsRead", "CreatedAt");
+
+                    b.ToTable("Notifications");
+                });
+
+            modelBuilder.Entity("Nexus.Api.Data.Project", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("Description")
+                        .IsRequired()
+                        .HasColumnType("text");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasMaxLength(160)
+                        .HasColumnType("character varying(160)");
+
+                    b.Property<int>("Progress")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("Status")
+                        .HasColumnType("integer");
+
+                    b.Property<DateTimeOffset>("UpdatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("Projects");
+                });
+
+            modelBuilder.Entity("Nexus.Api.Data.RefreshToken", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<Guid>("ConcurrencyStamp")
+                        .IsConcurrencyToken()
+                        .HasColumnType("uuid");
+
+                    b.Property<DateTimeOffset>("CreatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<DateTimeOffset>("ExpiresAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<Guid>("FamilyId")
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("ReplacedByTokenHash")
+                        .HasMaxLength(64)
+                        .HasColumnType("character varying(64)");
+
+                    b.Property<DateTimeOffset?>("RevokedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("TokenHash")
+                        .IsRequired()
+                        .HasMaxLength(64)
+                        .HasColumnType("character varying(64)");
+
+                    b.Property<Guid>("UserId")
+                        .HasColumnType("uuid");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("TokenHash")
+                        .IsUnique();
+
+                    b.HasIndex("UserId", "FamilyId");
+
+                    b.ToTable("RefreshTokens");
+                });
+
+            modelBuilder.Entity("Nexus.Api.Data.WorkTask", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("AssignedTo")
+                        .HasMaxLength(60)
+                        .HasColumnType("character varying(60)");
+
+                    b.Property<DateTimeOffset>("CreatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("Detail")
+                        .HasMaxLength(2000)
+                        .HasColumnType("character varying(2000)");
+
+                    b.Property<DateTimeOffset?>("DueDate")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<Guid?>("ParentTaskId")
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("Priority")
+                        .IsRequired()
+                        .HasColumnType("text");
+
+                    b.Property<Guid?>("ProjectId")
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("Source")
+                        .IsRequired()
+                        .HasMaxLength(60)
+                        .HasColumnType("character varying(60)");
+
+                    b.Property<string>("State")
+                        .IsRequired()
+                        .HasColumnType("text");
+
+                    b.Property<string>("Title")
+                        .IsRequired()
+                        .HasMaxLength(240)
+                        .HasColumnType("character varying(240)");
+
+                    b.Property<DateTimeOffset>("UpdatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("AssignedTo");
+
+                    b.HasIndex("ParentTaskId");
+
+                    b.HasIndex("Source");
+
+                    b.ToTable("Tasks");
+                });
+
+            modelBuilder.Entity("Nexus.Api.Data.RefreshToken", b =>
+                {
+                    b.HasOne("Nexus.Api.Data.NexusUser", "User")
+                        .WithMany("RefreshTokens")
+                        .HasForeignKey("UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("User");
+                });
+
+            modelBuilder.Entity("Nexus.Api.Data.WorkTask", b =>
+                {
+                    b.HasOne("Nexus.Api.Data.WorkTask", "ParentTask")
+                        .WithMany("ChildTasks")
+                        .HasForeignKey("ParentTaskId")
+                        .OnDelete(DeleteBehavior.SetNull);
+
+                    b.Navigation("ParentTask");
+                });
+
+            modelBuilder.Entity("Nexus.Api.Data.NexusUser", b =>
+                {
+                    b.Navigation("RefreshTokens");
+                });
+
+            modelBuilder.Entity("Nexus.Api.Data.WorkTask", b =>
+                {
+                    b.Navigation("ChildTasks");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}

backend/Data/Migrations/20260618214335_AddNotifications.cs

@@ -0,0 +1,45 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace Nexus.Api.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddNotifications : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.CreateTable(
+                name: "Notifications",
+                columns: table => new
+                {
+                    Id = table.Column<Guid>(type: "uuid", nullable: false),
+                    Type = table.Column<string>(type: "character varying(60)", maxLength: 60, nullable: false),
+                    Title = table.Column<string>(type: "character varying(240)", maxLength: 240, nullable: false),
+                    Message = table.Column<string>(type: "character varying(1000)", maxLength: 1000, nullable: true),
+                    ForUser = table.Column<string>(type: "character varying(60)", maxLength: 60, nullable: false),
+                    TaskId = table.Column<Guid>(type: "uuid", nullable: true),
+                    IsRead = table.Column<bool>(type: "boolean", nullable: false),
+                    CreatedAt = table.Column<DateTimeOffset>(type: "timestamp with time zone", nullable: false)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_Notifications", x => x.Id);
+                });
+
+            migrationBuilder.CreateIndex(
+                name: "IX_Notifications_ForUser_IsRead_CreatedAt",
+                table: "Notifications",
+                columns: new[] { "ForUser", "IsRead", "CreatedAt" });
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropTable(
+                name: "Notifications");
+        }
+    }
+}

backend/Data/Migrations/20260618233000_AddTaskParentChild.cs

@@ -0,0 +1,49 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace Nexus.Api.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddTaskParentChild : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<Guid>(
+                name: "ParentTaskId",
+                table: "Tasks",
+                type: "uuid",
+                nullable: true);
+
+            migrationBuilder.CreateIndex(
+                name: "IX_Tasks_ParentTaskId",
+                table: "Tasks",
+                column: "ParentTaskId");
+
+            migrationBuilder.AddForeignKey(
+                name: "FK_Tasks_Tasks_ParentTaskId",
+                table: "Tasks",
+                column: "ParentTaskId",
+                principalTable: "Tasks",
+                principalColumn: "Id",
+                onDelete: ReferentialAction.SetNull);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropForeignKey(
+                name: "FK_Tasks_Tasks_ParentTaskId",
+                table: "Tasks");
+
+            migrationBuilder.DropIndex(
+                name: "IX_Tasks_ParentTaskId",
+                table: "Tasks");
+
+            migrationBuilder.DropColumn(
+                name: "ParentTaskId",
+                table: "Tasks");
+        }
+    }
+}

backend/Data/Migrations/20260618233001_AddTaskDueDate.cs

@@ -0,0 +1,28 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace Nexus.Api.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddTaskDueDate : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<DateTimeOffset>(
+                name: "DueDate",
+                table: "Tasks",
+                type: "timestamp with time zone",
+                nullable: true);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "DueDate",
+                table: "Tasks");
+        }
+    }
+}

backend/Data/Migrations/20260618233002_AddActivityTaskReference.cs

@@ -0,0 +1,37 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace Nexus.Api.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddActivityTaskReference : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<Guid>(
+                name: "TaskId",
+                table: "Activity",
+                type: "uuid",
+                nullable: true);
+
+            migrationBuilder.CreateIndex(
+                name: "IX_Activity_TaskId",
+                table: "Activity",
+                column: "TaskId");
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropIndex(
+                name: "IX_Activity_TaskId",
+                table: "Activity");
+
+            migrationBuilder.DropColumn(
+                name: "TaskId",
+                table: "Activity");
+        }
+    }
+}

backend/Data/Migrations/20260618233003_AddDelegatedState.Designer.cs

@@ -0,0 +1,270 @@
+// <auto-generated />
+using System;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+using Nexus.Api.Data;
+using Npgsql.EntityFrameworkCore.PostgreSQL.Metadata;
+
+#nullable disable
+
+namespace Nexus.Api.Migrations
+{
+    [DbContext(typeof(NexusDbContext))]
+    [Migration("20260618233003_AddDelegatedState")]
+    partial class AddDelegatedState
+    {
+        /// <inheritdoc />
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder
+                .HasAnnotation("ProductVersion", "10.0.8")
+                .HasAnnotation("Relational:MaxIdentifierLength", 63);
+
+            NpgsqlModelBuilderExtensions.UseIdentityByDefaultColumns(modelBuilder);
+
+            modelBuilder.Entity("Nexus.Api.Data.ActivityEvent", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("bigint");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<long>("Id"));
+
+                    b.Property<DateTimeOffset>("CreatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("Message")
+                        .IsRequired()
+                        .HasMaxLength(1000)
+                        .HasColumnType("character varying(1000)");
+
+                    b.Property<Guid?>("TaskId")
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("Type")
+                        .IsRequired()
+                        .HasColumnType("text");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("CreatedAt");
+
+                    b.HasIndex("TaskId");
+
+                    b.ToTable("Activity");
+                });
+
+            modelBuilder.Entity("Nexus.Api.Data.NexusUser", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<DateTimeOffset>("CreatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("DisplayName")
+                        .IsRequired()
+                        .HasMaxLength(100)
+                        .HasColumnType("character varying(100)");
+
+                    b.Property<string>("Email")
+                        .IsRequired()
+                        .HasMaxLength(120)
+                        .HasColumnType("character varying(120)");
+
+                    b.Property<DateTimeOffset?>("LastLoginAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("NormalizedEmail")
+                        .IsRequired()
+                        .HasMaxLength(120)
+                        .HasColumnType("character varying(120)");
+
+                    b.Property<string>("PasswordHash")
+                        .IsRequired()
+                        .HasColumnType("text");
+
+                    b.Property<string>("Role")
+                        .IsRequired()
+                        .HasColumnType("text");
+
+                    b.Property<DateTimeOffset>("UpdatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("NormalizedEmail")
+                        .IsUnique();
+
+                    b.ToTable("Users");
+                });
+
+            modelBuilder.Entity("Nexus.Api.Data.Project", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("Description")
+                        .IsRequired()
+                        .HasColumnType("text");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasMaxLength(160)
+                        .HasColumnType("character varying(160)");
+
+                    b.Property<int>("Progress")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("Status")
+                        .HasColumnType("integer");
+
+                    b.Property<DateTimeOffset>("UpdatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("Projects");
+                });
+
+            modelBuilder.Entity("Nexus.Api.Data.RefreshToken", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<Guid>("ConcurrencyStamp")
+                        .IsConcurrencyToken()
+                        .HasColumnType("uuid");
+
+                    b.Property<DateTimeOffset>("CreatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<DateTimeOffset>("ExpiresAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<Guid>("FamilyId")
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("ReplacedByTokenHash")
+                        .HasMaxLength(64)
+                        .HasColumnType("character varying(64)");
+
+                    b.Property<DateTimeOffset?>("RevokedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("TokenHash")
+                        .IsRequired()
+                        .HasMaxLength(64)
+                        .HasColumnType("character varying(64)");
+
+                    b.Property<Guid>("UserId")
+                        .HasColumnType("uuid");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("TokenHash")
+                        .IsUnique();
+
+                    b.HasIndex("UserId", "FamilyId");
+
+                    b.ToTable("RefreshTokens");
+                });
+
+            modelBuilder.Entity("Nexus.Api.Data.WorkTask", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("AssignedTo")
+                        .HasMaxLength(60)
+                        .HasColumnType("character varying(60)");
+
+                    b.Property<DateTimeOffset>("CreatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("Detail")
+                        .HasMaxLength(2000)
+                        .HasColumnType("character varying(2000)");
+
+                    b.Property<DateTimeOffset?>("DueDate")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<Guid?>("ParentTaskId")
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("Priority")
+                        .IsRequired()
+                        .HasColumnType("text");
+
+                    b.Property<Guid?>("ProjectId")
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("Source")
+                        .IsRequired()
+                        .HasMaxLength(60)
+                        .HasColumnType("character varying(60)");
+
+                    b.Property<string>("State")
+                        .IsRequired()
+                        .HasColumnType("text");
+
+                    b.Property<string>("Title")
+                        .IsRequired()
+                        .HasMaxLength(240)
+                        .HasColumnType("character varying(240)");
+
+                    b.Property<DateTimeOffset>("UpdatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("AssignedTo");
+
+                    b.HasIndex("ParentTaskId");
+
+                    b.HasIndex("Source");
+
+                    b.ToTable("Tasks");
+                });
+
+            modelBuilder.Entity("Nexus.Api.Data.RefreshToken", b =>
+                {
+                    b.HasOne("Nexus.Api.Data.NexusUser", "User")
+                        .WithMany("RefreshTokens")
+                        .HasForeignKey("UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("User");
+                });
+
+            modelBuilder.Entity("Nexus.Api.Data.WorkTask", b =>
+                {
+                    b.HasOne("Nexus.Api.Data.WorkTask", "ParentTask")
+                        .WithMany("ChildTasks")
+                        .HasForeignKey("ParentTaskId")
+                        .OnDelete(DeleteBehavior.SetNull);
+
+                    b.Navigation("ParentTask");
+                });
+
+            modelBuilder.Entity("Nexus.Api.Data.NexusUser", b =>
+                {
+                    b.Navigation("RefreshTokens");
+                });
+
+            modelBuilder.Entity("Nexus.Api.Data.WorkTask", b =>
+                {
+                    b.Navigation("ChildTasks");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}

backend/Data/Migrations/20260618233003_AddDelegatedState.cs

@@ -0,0 +1,24 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace Nexus.Api.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddDelegatedState : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            // Delegated state is a pure code change to the TaskState enum and
+            // TaskStateHelper. No schema change required since the State column
+            // is already a free-form string column.
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            // No schema to revert.
+        }
+    }
+}

backend/Data/Migrations/NexusDbContextModelSnapshot.cs

@@ -38,12 +38,19 @@ namespace Nexus.Api.Migrations
                         .HasMaxLength(1000)
                         .HasColumnType("character varying(1000)");
 
+                    b.Property<Guid?>("TaskId")
+                        .HasColumnType("uuid");
+
                     b.Property<string>("Type")
                         .IsRequired()
                         .HasColumnType("text");
 
                     b.HasKey("Id");
 
+                    b.HasIndex("CreatedAt");
+
+                    b.HasIndex("TaskId");
+
                     b.ToTable("Activity");
                 });
 
@@ -93,6 +100,47 @@ namespace Nexus.Api.Migrations
                     b.ToTable("Users");
                 });
 
+            modelBuilder.Entity("Nexus.Api.Data.Notification", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<DateTimeOffset>("CreatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("ForUser")
+                        .IsRequired()
+                        .HasMaxLength(60)
+                        .HasColumnType("character varying(60)");
+
+                    b.Property<bool>("IsRead")
+                        .HasColumnType("boolean");
+
+                    b.Property<string>("Message")
+                        .HasMaxLength(1000)
+                        .HasColumnType("character varying(1000)");
+
+                    b.Property<Guid?>("TaskId")
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("Title")
+                        .IsRequired()
+                        .HasMaxLength(240)
+                        .HasColumnType("character varying(240)");
+
+                    b.Property<string>("Type")
+                        .IsRequired()
+                        .HasMaxLength(60)
+                        .HasColumnType("character varying(60)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("ForUser", "IsRead", "CreatedAt");
+
+                    b.ToTable("Notifications");
+                });
+
             modelBuilder.Entity("Nexus.Api.Data.Project", b =>
                 {
                     b.Property<Guid>("Id")
@@ -183,6 +231,12 @@ namespace Nexus.Api.Migrations
                         .HasMaxLength(2000)
                         .HasColumnType("character varying(2000)");
 
+                    b.Property<DateTimeOffset?>("DueDate")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<Guid?>("ParentTaskId")
+                        .HasColumnType("uuid");
+
                     b.Property<string>("Priority")
                         .IsRequired()
                         .HasColumnType("text");
@@ -211,6 +265,8 @@ namespace Nexus.Api.Migrations
 
                     b.HasIndex("AssignedTo");
 
+                    b.HasIndex("ParentTaskId");
+
                     b.HasIndex("Source");
 
                     b.ToTable("Tasks");
@@ -227,10 +283,25 @@ namespace Nexus.Api.Migrations
                     b.Navigation("User");
                 });
 
+            modelBuilder.Entity("Nexus.Api.Data.WorkTask", b =>
+                {
+                    b.HasOne("Nexus.Api.Data.WorkTask", "ParentTask")
+                        .WithMany("ChildTasks")
+                        .HasForeignKey("ParentTaskId")
+                        .OnDelete(DeleteBehavior.SetNull);
+
+                    b.Navigation("ParentTask");
+                });
+
             modelBuilder.Entity("Nexus.Api.Data.NexusUser", b =>
                 {
                     b.Navigation("RefreshTokens");
                 });
+
+            modelBuilder.Entity("Nexus.Api.Data.WorkTask", b =>
+                {
+                    b.Navigation("ChildTasks");
+                });
 #pragma warning restore 612, 618
         }
     }