fix(activity): make the recap actionable

[lilyshen0722]

Fixes TASK-083.

• Default scope is Active pods: every accessible pod with at least one substantive non-system agent message in the selected window. The recap returns each pod's activeInWindow and agentMessageCount; the native selector groups active and other pods, with explicit All pods.
• Needs you projects durable board facts as distinct press (gated PR, Open PR), decide (DECIDE, Open row), and handoff (human press, Open row) rows ahead of incidental mentions.
• The agent recap excludes common system senders and ranks real agent cards by message count, then recency.

Proof:

• backend: npm test -- --runInBand __tests__/unit/models/PgMessage.test.js __tests__/unit/services/activityService.recap.test.js — 19 passed
• backend typecheck; frontend V2ActivityPage + layout-invariant suites — 61 passed; frontend typecheck and production build passed
• The required real-account 1280px/390px captures with the native selector open are pending a deployable authenticated surface. Prior fixture captures are intentionally not offered as gate evidence.

Known baseline: repo-wide lint remains pre-existingly red (missing CLI eslint plus unrelated parser/import/i18n errors); changed files' focused behavior and build checks are green.

[lilyshen0722]

UX gate (ux-lead) at 3b893985 — changes requested, one item.

Blocking: the 1280/390 captures are fixture data (release-agent / security-agent, TASK-412, "Launch readiness"). TASK-083 was measured by Sam on prod, and the gate asked for captures on Sam's real account so we can see the actual outcome: default scope populated, no commonly-bot card, ≥1 press/decision row derived from the live board. A fixture proves the render, not the fix. Please re-capture against prod data (dev deploy or local pointed at prod API) and attach.

Verified in the diff and fine to ship as-is: press/decision kinds with "Open board" → /v2/pods/:podId/board (route exists, test covers it); system actors excluded from recap; scope defaults to active and the select lists only active pods; 390px controls fit.

Non-blocking nits, follow-up or now:

• Decision mark uses --v2-danger-soft; a decision is not an error — use the warning tone like press/approval.
• needsYou.emptyDescription still says "New mentions and approval requests" — add decisions and press-ready work.
• Select options carry no counts; design asked for "(N)" suffixes. Fine to defer.