fix(hooks,test): harden background rewake, fix hook timeout units, stabilize CI teardown

Follow-ups from the PR #175/#176 reviews:

- Rewake helper self-terminates on its own 6h deadline and when orphaned,
  instead of relying on Claude Code to reap the poller
- Rewake marker versioned (V2) with a version-agnostic ownership prefix, so
  future script updates replace older handlers instead of duplicating them;
  regression test covers the V1 to V2 swap
- HOOK_TIMEOUT_MS renamed to HOOK_TIMEOUT_SECONDS = 10: the hook timeout
  field is seconds (the CLI multiplies by 1000), so the curl hooks have
  effectively had a ~2.8h timeout since COD-54
- Test echo PTY switches to raw mode: each input byte echoes exactly once
  (tty line discipline doubled every line and buffered until Enter)
- test/setup.ts: drain in-flight console-log rpc forwards before environment
  teardown (fixes the EnvironmentTeardownError that failed CI twice on the
  merge commit with all 3820 tests passing), clean the temp home on process
  exit (fully-skipped files leaked it), fix the Windows Playwright cache
  fallback path
- test/webview-proxy.test.ts: stop naming the vitest environment directive in
  prose; vitest matches it inside comments and silently ran the whole file
  under the jsdom environment while the comment claimed node
- CLAUDE.md: document the temp-HOME and echo-PTY test isolation

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

test/hook-secret-selfheal.test.ts

@@ -127,7 +127,7 @@ describe('refreshStaleCodemanHooks', () => {
 
     const after = JSON.parse(readFileSync(settingsPath, 'utf-8'));
     expect(JSON.stringify(after.hooks)).toContain(SECRET_HEADER);
-    expect(JSON.stringify(after.hooks)).toContain('CODEMAN_BACKGROUND_REWAKE_V1');
+    expect(JSON.stringify(after.hooks)).toContain('CODEMAN_BACKGROUND_REWAKE_V');
     expect(JSON.stringify(after.hooks.Stop)).toContain('./notify-user.sh');
     expect(after.hooks.PostToolUse).toEqual(expect.arrayContaining([customPostToolUse]));
     expect(after.hooks.CustomEvent).toEqual(customEvent);