feat(ui): add the agent board panel and tasks search over ListAgentBoards (RIG-5409)

[rigel-mintaka]

This PR is part of a stack containing 4 PRs:

1. main
2. feat(ui): board summary badges in the sidebar and FleetPane (RIG-5177) #2290
3. feat(board): show asks and their forge mirror state on boards (RIG-5173) #2292
4. "feat(ui): add the agent board panel and tasks search over ListAgentBoards (RIG-5409)" (this PR)
5. feat(mirror): agent forge_mirror_messages tool with real-session attribution (RIG-5174) #2319

Summary

Finishes the UI half of the agent board (T9, D9 in docs/designs/agent/compass-agent-status-record/design.md) over ListAgentBoards.

• AgentBoardPanel in AgentView, on its own row under the header line. It shows:
  • the halt chip, focus task, "updated N min ago", and the stale marker;
  • one row per task: primary ref link, title, state, then refs with derived chips (gate, checks, draft, stack n/m, tip, stale approval), the note, waiting chips with their blocks refs, and subagents;
  • Asks, pending first;
  • Untracked refs.
• The panel reads ListAgentBoards for its agent through the shared query cache. It re-reads every 60 s and on each AgentBoardChanged for the agent, counted per agent in comms presence (boardEvents), because an automatic patch keeps the write time.
• A primary ref with an unsafe URL renders as plain text; a safe one opens through openExternal.
• Clicking an ask opens the topic that holds its message. When that message is not loaded, it opens the ask's channel.
• tasks destination provider (kind task): matches task title and note text, and does an exact ref read when the query looks like a ref. Rows keep server order across boards. Selecting a row opens the agent.

Stack

On #2292 (asks and mirror state on boards). Below it: #2290 → #2285 → #2275 → main.

Tests

• AgentBoard.test.tsx: the panel renders tasks, derived chips, waiting chips, subagents, asks (pending first) and untracked refs from a fixture.
• AgentBoard.test.tsx also: a safe primary ref opens externally; an unsafe one renders as text.
• AgentBoardPanel.live.test.tsx:
  • an agentBoardChanged re-reads the board exactly once;
  • two automatic patches with the same write time each re-read;
  • an ask whose message is not loaded opens its channel.
• destinations.test.ts: the tasks provider finds a ref (and tolerates a refused ref read) and opens the agent; rows keep server order across boards.
• Each test was checked red against a mutation: refetch removed, event counter removed, click handler removed, unsafe fallback reverted, provider navigation removed, per-board rank restored.
• compass-ui:test 1614 pass, 0 fail; typecheck, stylelint and the visual gate (19 passed) green.

Refs RIG-5409

[linear-code]

RIG-5409

RIG-5173

[github-actions]

Compass engineering docs preview: https://compass-ux-5409-board-panel.compass-eng-docs.pages.dev

Deployed from compass-ux/5409-board-panel at ed3987f.

[rigel-mintaka]

Review result

• reviewedSha: 6f1ae8e0ed5e77f7976ed2e03376e5b315b6143a
• reviewedBase: 1e8efc49e0ab49266a84b2626cda5e82f13abbef
• Result: all-clear (0 high, 0 medium open)

Notes: round 1 on 2900a9c found 2 medium and 1 low.

• An automatic board patch keeps the write time, so the panel could miss a re-read. The panel now counts board events per agent.
• No test covered the primary-ref link. The new tests found that an unsafe URL rendered empty text, which is now fixed.
• Task rank restarted per board. Rows now keep server order.

The fixes are in 6f1ae8e, and round 2 found 0 findings. Each new test fails against its mutation.

Gates: compass-ui:test 1614 pass, 0 fail; typecheck, stylelint and the visual gate (19 passed) green; pre-push hooks passed; CI green at this head.

[rigel-mintaka]

Review result

• reviewedSha: 8e9da03138017d55250a6415cf71d2179ac99645
• reviewedBase: 1d3ec69a655c46dfd7efd77b57062ab5a29bcb36
• Result: all-clear (0 high, 0 medium open)

Notes: Rebased onto #2292 1d3ec69 after compass-comms rebased the board line onto main 22d9fc0; empty interdiff against c89d5f0. compass-ui test 1635 pass, typecheck, stylelint and visual gate (19) green. The prior all-clear at 6f1ae8e carries.

Gates: latest CI run green at this head; pre-push hooks passed.

[rigel-mintaka]

Review result

• reviewedSha: ed3987f00d755a4eb5f4d02d49fc8370a6f006c8
• reviewedBase: e48fecd8e289206598027d25477e6d8201b4156d
• Result: all-clear (0 high, 0 medium open)

Notes: Pure rebase by compass-comms onto #2292 e48fecd (itself rebased onto main 888ac07). git range-diff bfd7187..8e9da03 cad170c..ed3987f shows = for both commits; the interdiff against 8e9da03 is empty. The prior all-clear at ed3987f carries.

Gates: latest CI run green at this head; pre-push hooks passed.