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>

mcp_server/TOOLS.md

@@ -73,6 +73,19 @@ Use `list_human_interventions()` at session start to see Bernd's action items.
 
 ---
 
+## Token Consumption Tools
+
+Record and query AI token usage at task/workstream/repo/commit/release granularity.
+Agents should call `record_token_event` (or pass `tokens_in`/`tokens_out` via
+`update_task_status`) at task completion.
+
+| Tool | Key Args | Notes |
+|------|----------|-------|
+| `record_token_event(tokens_in, tokens_out, ...)` | `task_id`?, `workstream_id`?, `repo_id`?, `model`?, `agent`?, `ref_type`?, `ref_id`?, `note`?, `session_id`? | POSTs to `/token-events/`. `workstream_id` auto-filled from task. Returns event id + running total. |
+| `get_token_summary(scope, id)` | `scope`: task\|workstream\|repo\|commit\|release\|session; `id`: UUID or ref string | Returns formatted table of tokens_in/out/total, event_count, by_model, by_agent. |
+
+---
+
 ## Governance Tools
 
 | Tool | Key Args | When to use |