feat: complete Nexus mission-control workflows

backend/Models/Dashboard.cs

@@ -14,6 +14,8 @@ public sealed record DashboardAgentInfo(
     string? Goal = null,
     string RoleBadge = "badge-slate",
     string StatusLabel = "Bereit",
+    string StatusKind = "ready",
+    string? StatusDetail = null,
     string? Elapsed = null,
     string? Think = null,
     string? Next = null
@@ -136,7 +138,22 @@ public sealed record UpdateDashboardTaskStatusRequest(
 
 public sealed record AgentActivityEntry(
     string Time,
-    string Text
+    string Text,
+    DateTimeOffset Timestamp,
+    string Source = "gateway-session-history"
+);
+
+public sealed record GatewayRuntimeInfo(
+    bool Reachable,
+    string BaseUrl,
+    string? Version,
+    string? RequiredVersion,
+    bool VersionPinned,
+    bool VersionMatches,
+    string VersionStatus,
+    DateTimeOffset CheckedAt,
+    string? Message,
+    string? Warning = null
 );
 
 // ── Task Board DTOs ──