feat(goals): add domain/repo goal tracking and update_workstream MCP tool

- Migration c5d6e7f8a9b0: domain_goals and repo_goals tables, repo_goal_id FK on workstreams
- DomainGoal: one active per domain (partial unique index), status active/archived/superseded
- RepoGoal: integer priority, status active/paused/completed/archived, optional domain_goal_id link
- WorkstreamUpdate schema and router extended with repo_goal_id and repo_goal_id filter
- 6 new MCP goal tools: create_domain_goal, get_domain_goals, activate_domain_goal, create_repo_goal, get_repo_goals, update_repo_goal
- update_workstream MCP tool: patch any subset of workstream fields (title, description, owner, due_date, repo_goal_id, status)
- get_domain_summary extended with goal_guidance (needs_workplan, alignment_warnings) signals
- Dashboard goals.md page and docs/goals.md reference page
- CLAUDE.md template updated to act on goal_guidance signals at session start
- CUST-WP-0010 workplan for this feature

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

mcp_server/TOOLS.md

@@ -54,7 +54,8 @@ Do not use them as a substitute for formal work definition inside the domain rep
 | `create_workstream(topic_id, title, ...)` | `slug?`; `owner?`; `description?`; `due_date?` | Creates workstream under a topic. Use `get_state_summary()` to find topic IDs. |
 | `create_task(workstream_id, title, ...)` | `priority`: low/medium/high/critical; `assignee?`; `due_date?` | Creates task under a workstream. |
 | `update_task_status(task_id, status, ...)` | `status`: todo/in_progress/blocked/done/cancelled; `blocking_reason` required when blocked | |
-| `update_workstream_status(workstream_id, status)` | `status`: active/blocked/completed/archived | |
+| `update_workstream_status(workstream_id, status)` | `status`: active/blocked/completed/archived | Thin shortcut — use `update_workstream` for full field control. |
+| `update_workstream(workstream_id, ...)` | `title?`; `description?`; `owner?`; `due_date?`; `repo_goal_id?`; `status?` | Patch any subset of workstream fields. Pass empty string for `repo_goal_id` to clear the link. |
 
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