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.

backend/test/workspace-runtime-handoff.test.ts

@@ -197,6 +197,25 @@ test("ThtRunner uses a vault secret only for the lifetime of its runtime lease",
   expect(existsSync(rendered.database.password_file)).toBe(false);
 });
 
+test("ThtRunner binds and cleans the effective relationship snapshot with its runtime lease", async () => {
+  const f = await fixture();
+  const runner = runnerFor(f);
+  const relationships = JSON.stringify({
+    schemaVersion: 1,
+    workspaceId: "psd-clinical",
+    relationships: [],
+  });
+
+  const lease = runner.acquireWorkspaceRuntime(f.revision.snapshotPath, relationships);
+  const rendered = parse(readFileSync(lease.path, "utf8")) as {
+    paths: { effective_relationships: string };
+  };
+
+  expect(readFileSync(rendered.paths.effective_relationships, "utf8")).toBe(relationships);
+  lease.release();
+  expect(existsSync(rendered.paths.effective_relationships)).toBe(false);
+});
+
 test("separate runtime leases hand off byte-identical revision Evidence configs accepted by tht", async () => {
   const f = await fixture();
   const runner = runnerFor(f);