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>

workplans/CUST-WP-0029-token-consumption-tracking.md

@@ -4,7 +4,7 @@ type: workplan
 title: "Token Consumption Tracking"
 domain: custodian
 repo: the-custodian
-status: active
+status: done
 owner: custodian
 topic_slug: custodian
 created: "2026-03-29"
@@ -239,7 +239,7 @@ for an agent running a loop.
 
 ```task
 id: CUST-WP-0029-T08
-status: todo
+status: done
 priority: high
 state_hub_task_id: "a3627144-9d98-4a3b-aa64-3079fd087448"
 ```