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.

internal/deployer/bluegreen.go

@@ -117,6 +117,7 @@ func (d *Deployer) blueGreenDeploy(
 		WorkloadID:   workloadID,
 		WorkloadKind: string(store.WorkloadKindProject),
 		Role:         stage.Name,
+		StageID:      stage.ID,
 		ContainerID:  containerID,
 		ImageRef:     project.Image + ":" + imageTag,
 		ImageTag:     imageTag,

internal/deployer/deployer.go

@@ -413,6 +413,7 @@ func (d *Deployer) executeDeploy(
 		WorkloadID:   workloadID,
 		WorkloadKind: string(store.WorkloadKindProject),
 		Role:         stage.Name,
+		StageID:      stage.ID,
 		ContainerID:  containerID,
 		ImageRef:     project.Image + ":" + imageTag,
 		ImageTag:     imageTag,