feat(token-tracking): record AI token consumption per task (CUST-WP-0029)

Introduces end-to-end token consumption tracking so agent work is
visible as a cost/effort metric alongside tasks and workplans.

- Migration o2j3k4l5m6n7: token_events table with FK indexes on
  task_id, workstream_id, repo_id, created_at
- ORM model, Pydantic schemas (TokenEventCreate, TokenEventRead with
  computed tokens_total, TokenSummary)
- Router: POST /token-events/, GET /token-events/ (7 filters),
  GET /token-events/summary/ (task|workstream|repo|commit|release scope)
- MCP tools: record_token_event, get_token_summary (formatted table)
- update_task_status enriched with optional tokens_in/tokens_out
  passthrough — one call creates status update + token event
- Dashboard token-cost.md page: by-repo bar, by-workplan table,
  by-model bar, top-10 tasks by tokens
- ralph-workplan skill updated with token reporting guidance and
  per-task heuristics for estimating counts
- Tests: test_token_events.py + test_token_passthrough.py (182 pass)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

api/main.py

@@ -7,6 +7,7 @@ from fastapi.middleware.cors import CORSMiddleware
 from api.database import engine
 from api.routers import decisions, extension_points, progress, state, tasks, technical_debt, topics, workstreams, workstream_dependencies
 from api.routers import domains, repos, contributions, sbom, policy, domain_goals, repo_goals, messages, capability_requests, tpsc
+from api.routers import token_events
 
 
 @asynccontextmanager
@@ -49,6 +50,7 @@ app.include_router(sbom.router)
 app.include_router(messages.router)
 app.include_router(capability_requests.router)
 app.include_router(tpsc.router)
+app.include_router(token_events.router)
 app.include_router(state.router)
 app.include_router(policy.router)