feat: consolidate database management work

Add catalog-owned logical relationships and runtime snapshots, extend the database-management UI and validation coverage, and document the updated operational workflow.

Keep active sensitive-generation status in a tooltip and indicator, and update the layout E2E to follow the history action in its new database-scoped location.

frontend/src/index.css

@@ -47,6 +47,12 @@
     --success: 0.7577 0.1581 165.0;
     --warning: 0.8523 0.1386 78.9;
     --info: 0.7035 0.1128 221.3;
+    /* Current navigation shares Instrument Red's hue, with lower chroma and
+       higher lightness so selection reads as a muted location signal. */
+    --nav-active: 0.9250 0.0520 23.2;
+    --nav-active-hover: 0.8950 0.0710 23.2;
+    --nav-active-foreground: 0.3650 0.1100 23.2;
+    --nav-active-border: 0.6000 0.1350 23.2;
     --radius: 0.5rem;
     --sidebar: 0.9709 0.0011 17.2;
     --sidebar-foreground: 0.2678 0.0097 355.6;
@@ -81,6 +87,10 @@
     --border: 0.3715 0 90;
     --input: 0.3715 0 90;
     --ring: 0.6897 0.1779 16.9;
+    --nav-active: 0.3350 0.0550 20.3;
+    --nav-active-hover: 0.3750 0.0650 20.3;
+    --nav-active-foreground: 0.8900 0.0700 20.3;
+    --nav-active-border: 0.6800 0.1350 20.3;
     --sidebar: 0.2350 0 90;
     --sidebar-foreground: 0.9310 0 90;
     --sidebar-primary: 0.6023 0.1848 20.3;