feat: align LegacyHUB with TeamHUB platform contract (D2/D4, assets, security)

Close 12 audit-driven platform-compliance gaps on a single branch.

- D4 dispatch: app/integrations/dispatch_client.py participant `legacyhub`,
  emits LegacyhubDocumentIndexed + AssetDerivativeReady after the indexing
  commit (idempotent uuid5), http_inbox route (reindex/tombstone) with
  audit-based dedupe; docs/dispatch-contract.md. Celery+Redis stays intra-module.
- D2 SSO: app/integrations/identity.py validates X-TeamHub-* + role/scope
  mapper; security.py adds trusted-header enforcement (AUTH_REQUIRE_IDENTITY)
  and a scope check on /search; docker-compose.teamhub.yml (external teamhub_net
  + internal db net, api not host-published); RUNBOOK network/firewall section.
- Asset standard: SearchHit/Citation carry asset_id/owner_module; buckets
  renamed teamhub-legacyhub-* (+quarantine/tmp/exports); purge-by-asset_id with
  legal-hold guard (app/indexing/projection.py); OCR-markdown derivative event.
- audit_log model + Alembic 0003 + record_audit on writes (same transaction).
- Secret masking: app/common/json_logger.py recursive mask wired into structlog
  (+ensure_ascii=False); event payloads redacted before persistence.
- Service X-API-Key mandatory on ingest endpoints (defence-in-depth).
- Port: host API 8000->8050 (collision with SalesHUB/MailHUB resolved),
  container still listens on 8000.
- Config: no plaintext secret defaults; fail-loud in non-dev (no value leak).
- Docs drift: README PG 5440, layered-auth note, 5173 removed from CORS;
  ingest/folder gated by ENABLE_FOLDER_INGEST (410 by default).
- ADRs: layers mapping, shared-core extraction, UI locale (RU-first).

Tests: 78 passing (ruff, compileall, pytest, tsc, vite build, compose config).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/README.md

@@ -41,11 +41,11 @@ This package ships:
 cd frontend
 cp .env.example .env       # VITE_USE_MOCK=true for offline UI development
 npm install
-npm run dev                # http://localhost:5173
+npm run dev                # http://localhost:5273
 ```
 
 When the FastAPI backend is running, set `VITE_USE_MOCK=false` (or simply
-`VITE_API_BASE_URL=/api/v1` and let the Vite dev proxy at port 8000 handle
+`VITE_API_BASE_URL=/api/v1` and let the Vite dev proxy at port 8050 handle
 routing). All API calls are isolated through `src/services/*.ts`.
 
 ## Architecture
@@ -132,7 +132,7 @@ running.
 ## Scripts
 
 ```bash
-npm run dev        # Vite dev server with /api proxy → :8000
+npm run dev        # Vite dev server with /api proxy → :8050
 npm run build      # type-check + production bundle
 npm run preview    # preview build
 npm run lint

frontend/vite.config.ts

@@ -14,7 +14,7 @@ export default defineConfig({
     strictPort: true,
     proxy: {
       "/api": {
-        target: "http://localhost:8000",
+        target: "http://localhost:8050",
         changeOrigin: true,
       },
     },