fix(review): breaker reset semantics, trip observability, push template (PR #147)

- Breaker reset is now explicit-only: POST /api/sessions/:id/interactive no
  longer unconditionally resets the PTY-exit breaker (that endpoint IS the
  frontend's automatic re-attach path, so the breaker could never trip on the
  COD-115 crash loop and any tab click silently re-armed it). The route accepts
  a schema-validated optional body flag {clearBreaker:true}
  (InteractiveStartSchema) and resets only when it is sent.
- Frontend restart control: app.js selectSession keeps the bare auto-attach
  (no body, never clears); when the selected session has respawnBlocked it asks
  for explicit user confirmation and only then re-POSTs with clearBreaker:true.
  respawnBlocked is surfaced via SessionState/toState() (runtime-only, not
  restored on boot so recovery can re-attach).
- Trip observability: WebServer.setupSessionListeners() is now idempotent
  (skips while refs are attached) and the re-attach routes (/interactive,
  /interactive-respawn, /shell) re-run it, restoring the wiring that the exit
  handler detaches on every PTY exit — without this the 5th-exit trip had
  guaranteed zero listeners (no SSE, no push, no persist, no run-summary).
- Push notification: added SessionRespawnBreakerTripped to PUSH_EVENT_MAP
  ('Session crash loop stopped', urgency critical) with an exit-count body
  branch; previously sendPushNotifications silently no-oped.
- Minor: buildMuxAttachEnv() truecolor param is now actually passed
  (codex/gemini, mirrors buildEnvExports); buildClaudeEnv() uses delete for
  COLORTERM/CLAUDECODE (same node-pty "KEY=undefined" quirk as COD-115).
- Tests: route tests assert auto-reattach does NOT reset, clearBreaker resets,
  invalid flag rejected, and listener re-wiring on /interactive + /shell;
  real-wiring lifecycle tests (createSessionListeners/attach/detach) prove the
  exit-detach gap and that re-setup keeps the 5th-exit trip observable;
  PUSH_EVENT_MAP regression guard.

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

src/session-cli-builder.ts

@@ -102,14 +102,12 @@ export function buildPromptArgs(prompt: string, model?: string): string[] {
  * @returns Environment variables object for pty.spawn
  */
 export function buildClaudeEnv(sessionId: string): Record<string, string | undefined> {
-  return {
+  const env: Record<string, string | undefined> = {
     ...process.env,
     LANG: 'en_US.UTF-8',
     LC_ALL: 'en_US.UTF-8',
     PATH: getAugmentedPath(),
     TERM: 'xterm-256color',
-    COLORTERM: undefined,
-    CLAUDECODE: undefined,
     // Inform Claude it's running within Codeman (helps prevent self-termination)
     CODEMAN_MUX: '1',
     CODEMAN_SESSION_ID: sessionId,
@@ -117,6 +115,11 @@ export function buildClaudeEnv(sessionId: string): Record<string, string | undef
     // Path only (not the secret value) — hook curls cat it at execution time (COD-54)
     CODEMAN_HOOK_SECRET_FILE: dataPath('hook-secret'),
   };
+  // COD-115: `delete`, not `= undefined` — node-pty serializes a present-with-undefined
+  // key as the literal string "KEY=undefined" (see buildMuxAttachEnv below).
+  delete env.COLORTERM;
+  delete env.CLAUDECODE;
+  return env;
 }
 
 /**