fix(db): register legacy task migrations

backend/Data/Migrations/20260618233000_AddTaskParentChild.cs

@@ -1,49 +1,59 @@
+using Microsoft.EntityFrameworkCore.Infrastructure;
 using Microsoft.EntityFrameworkCore.Migrations;
+using Nexus.Api.Data;
 
 #nullable disable
 
 namespace Nexus.Api.Migrations
 {
     /// <inheritdoc />
+    [DbContext(typeof(NexusDbContext))]
+    [Migration("20260618233000_AddTaskParentChild")]
     public partial class AddTaskParentChild : Migration
     {
         /// <inheritdoc />
         protected override void Up(MigrationBuilder migrationBuilder)
         {
-            migrationBuilder.AddColumn<Guid>(
-                name: "ParentTaskId",
-                table: "Tasks",
-                type: "uuid",
-                nullable: true);
+            // This historical migration originally lacked EF discovery
+            // metadata. Keep the catch-up operations idempotent so existing
+            // installations and fresh PostgreSQL databases converge safely.
+            migrationBuilder.Sql(
+                """
+                ALTER TABLE "Tasks"
+                    ADD COLUMN IF NOT EXISTS "ParentTaskId" uuid;
 
-            migrationBuilder.CreateIndex(
-                name: "IX_Tasks_ParentTaskId",
-                table: "Tasks",
-                column: "ParentTaskId");
+                CREATE INDEX IF NOT EXISTS "IX_Tasks_ParentTaskId"
+                    ON "Tasks" ("ParentTaskId");
 
-            migrationBuilder.AddForeignKey(
-                name: "FK_Tasks_Tasks_ParentTaskId",
-                table: "Tasks",
-                column: "ParentTaskId",
-                principalTable: "Tasks",
-                principalColumn: "Id",
-                onDelete: ReferentialAction.SetNull);
+                DO $$
+                BEGIN
+                    IF NOT EXISTS (
+                        SELECT 1
+                        FROM pg_constraint
+                        WHERE conname = 'FK_Tasks_Tasks_ParentTaskId'
+                          AND conrelid = '"Tasks"'::regclass
+                    ) THEN
+                        ALTER TABLE "Tasks"
+                            ADD CONSTRAINT "FK_Tasks_Tasks_ParentTaskId"
+                            FOREIGN KEY ("ParentTaskId")
+                            REFERENCES "Tasks" ("Id")
+                            ON DELETE SET NULL;
+                    END IF;
+                END $$;
+                """);
         }
 
         /// <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");
+            migrationBuilder.Sql(
+                """
+                ALTER TABLE "Tasks"
+                    DROP CONSTRAINT IF EXISTS "FK_Tasks_Tasks_ParentTaskId";
+                DROP INDEX IF EXISTS "IX_Tasks_ParentTaskId";
+                ALTER TABLE "Tasks"
+                    DROP COLUMN IF EXISTS "ParentTaskId";
+                """);
         }
     }
 }