Address gaps identified in code review of the ActivityDetection PR:
Core / Session Manager:
- Add `timestamp` to all `{ state: "exited" }` returns in all 4 agent plugins
(claude-code, aider, codex, opencode) using consistent `exitedAt = new Date()` pattern
- Add 2 new session-manager tests: timestamp propagation when detection timestamp
is newer, and no-downgrade when detection timestamp is older
- Fix `parseJsonlFileTail` lint error: remove useless `= 0` initializer (value was
always overwritten before use; catch block returns early)
Web package — tests:
- Fix 3 `api-routes.test.ts` failures: `sessionsGET()` needs a Request object since
the route reads `request.url` for `?active=true` query param
- Fix `serialize.test.ts` rate-limit test: spy on `console.warn` (what the code uses)
not `console.error`
- Add 5 `ActivityDot` component tests covering all activity states, unknown states,
null activity, and dotOnly mode
Web package — UI correctness:
- Fix `relativeTime()` in SessionDetail to guard against invalid/empty ISO strings
- Fix timer Map leak: add `timersRef.current.clear()` in cleanup effect after forEach
- Add `encodeURIComponent` to sessionId in message fetch URL
Server — race condition fix:
- Guard `activeSessions.delete` in pty.onExit, ws.on("close"), and ws.on("error")
against stale handlers deleting a newly-registered session with the same ID.
Fixes flaky integration test where afterEach's pty.kill() fired asynchronously
after the next test had already set up a new session with the same session ID.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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