feat(frontend): add Readiness Matrix for configured/running/served/selected state

[OnlyTerp]

Closes #154

Adds a read-only Readiness Matrix panel to the dashboard that composes existing endpoints/hooks to clarify configured vs running vs served vs selected model state.

Changes

• New frontend/src/features/dashboard/readiness-matrix/ component family.
• Matrix displays per-recipe configured, process, served, selected, and mismatch status.
• Handles stopped, starting, running, error, and served-model mismatch states.
• Recipe name links to /recipes?id=... for editing.
• Adds tests/frontend/e2e/readiness-matrix.test.ts covering row-building logic.

Verification

• npm --prefix frontend run typecheck ✅
• npm --prefix frontend run lint ✅ (2 pre-existing warnings)
• npx tsx --test ../tests/frontend/e2e/readiness-matrix.test.ts ✅ 8 pass, 0 fail
• cd controller && bun run test:integration ✅ 48 pass / ❌ 1 unrelated failure (lifetime-metrics fixture asserts GPU power draw is 0; host reports real draw)
• npm run check:contracts ❌ upstream duplicate AggregatedSession export failure (see details below)

Known baseline failures (not from this PR)

1. controller integration lifetime-metrics fixture — the test expects current_power_watts: 0, but the workstation GPU reports a real value.
2. npm run check:contracts — flags duplicate AggregatedSession exports in frontend/src/app/api/agent/sessions/all/route.ts and frontend/src/features/agent/session-contracts.ts.

Non-goals

• No new backend aggregate endpoint.
• No auto-launch from chat.
• No recipe schema change.
• No permission/sandbox work.

[OnlyTerp]

Rebuilt from scratch on current main: re-homed from the retired src/components layer into features/dashboard, rendered with the @/ui kit (Card, Table, StatusPill) and ZCode tokens, fed entirely by props the dashboard layout already receives — no new stores, no polling, no useEffect. 8/8 model tests pass; check:quality green on push.