refactor(workload): finalize containers index + post-review hardening

Wraps up the workload refactor with the fixes that came out of the multi-agent
code review (see docs/plans/workload-refactor.md "What actually shipped").

Backend:
- store.ReconcileContainer: separate write path so the 30s reconciler tick no
  longer overwrites deployer-owned fields (subdomain, proxy_route_id,
  npm_proxy_id, image_tag).
- Container.stage_id column + index; ListProxyRoutes / ListContainersByStageID
  join via stage_id (survives stage rename), with legacy fallback to
  (project_id, role=stage_name).
- Reconciler: workload-existence check (rejects forged tinyforge.workload.id
  labels), skips inventing project-kind rows, child-context cancel before
  wg.Wait() on shutdown.
- Transactional CRUD across projects / stacks / static_sites: parent UPDATE
  and workload sync land in one transaction so secret rotations are durable.
- Webhook routing reads exclusively through workloads.webhook_secret; legacy
  GetProjectByWebhookSecret / GetStaticSiteByWebhookSecret fallback removed.
- store.GetStackByComposeProjectName + indexed lookup (no more full-table
  stack scan per compose container per tick).
- store.ListMissingSweepRows: filtered query for the missing-sweep.
- /api/instances/* handlers verify (workload_id, role) match URL
  (project_id, stage_name) before mutating — closes the cross-project
  hijack the security review flagged.
- extra_json no longer referenced from Go (column kept on disk for now).

Frontend:
- WorkloadContainers.svelte: generic detail-page panel reusable by stack and
  site detail pages.
- Containers page polish: client-side kind/state filters over an unfiltered
  fetch, URL-synced filters, race-safe loads via sequence number, EN+RU i18n,
  sidebar counter via navCounts.containers.

Misc:
- scripts/dev-server.sh: tolerate empty netstat grep result.
- .gitignore: ignore docker-watcher binaries, .claude/worktrees/, .facts-sync.json.

web/src/lib/i18n/en.json

@@ -732,6 +732,8 @@
     "loading": "Loading...",
     "noData": "No data",
     "project": "Project",
+    "stack": "Stack",
+    "site": "Site",
     "back": "Back",
     "actions": "Actions",
     "stop": "Stop",
@@ -743,7 +745,31 @@
     "next": "Next",
     "yes": "Yes",
     "no": "No",
-    "saving": "Saving..."
+    "saving": "Saving...",
+    "refresh": "Refresh",
+    "all": "All",
+    "running": "Running",
+    "stopped": "Stopped",
+    "missing": "Missing"
+  },
+  "containers": {
+    "errLoad": "Failed to load containers",
+    "searchPlaceholder": "Search workload, role, image, subdomain…",
+    "kindFilterLabel": "Workload kind",
+    "stateFilterLabel": "Container state",
+    "emptyTitle": "No containers",
+    "emptyDesc": "Deploy a project, stack, or site to see containers here.",
+    "noMatch": "No containers match the current filters.",
+    "showingN": "Showing {visible} of {total} containers",
+    "col": {
+      "workload": "Workload",
+      "kind": "Kind",
+      "role": "Role",
+      "image": "Image",
+      "state": "State",
+      "subdomain": "Subdomain",
+      "lastSeen": "Last seen"
+    }
   },
   "instance": {
     "stopConfirm": "This will stop the running container. The instance can be started again later.",