chore(openspec): drop 9 superseded proposals + 11 stub archive files

Drop 9 batch proposals that are superseded by the boocode-lift-analysis
(boocontext-audit, conductor upgrades, self-healing/verify-gate skills):
add-3tier-memory, import-llm-evaluator, import-pregel-engine, plugin-platform,
conductor-evolution, code-intelligence-upgrade, dev-workflow, ui-overhaul,
agent-reliability.

Delete 11 stub archive files (49-66B each, 'Status: Shipped. Archived.' only)
that provide zero documentation value over the existing CHANGELOG.md + git tags.

openspec/changes/pty-enhancements/tasks.md

@@ -0,0 +1,47 @@
+## 1. Add PTY exit notifications
+
+- [ ] 1.1 Extend booterm WS protocol to send `<pty_exited>` payload (exit code, last output, runtime)
+- [ ] 1.2 Wire into apps/coder so AI receives exit notification
+- [ ] 1.3 Add frontend display of exit status
+
+## 2. Add session metadata for PTY panes
+
+- [ ] 2.1 Add title, description, parentAgent, taskId fields to PTY session
+- [ ] 2.2 Store metadata in session store
+- [ ] 2.3 Display metadata in terminal pane header
+- [ ] 2.4 Allow AI agents to query metadata
+
+## 3. Add pattern-based log search
+
+- [ ] 3.1 Add pty_read with regex pattern filtering
+- [ ] 3.2 Add offset/limit pagination
+
+## 4. Add per-session timeouts
+
+- [ ] 4.1 Add timeoutSeconds parameter
+- [ ] 4.2 Implement auto-kill on timeout
+- [ ] 4.3 Send timeout exit notification
+
+## 5. Add sandbox circuit breaker
+
+- [ ] 5.1 Implement consecutive failure tracking (threshold: 2)
+- [ ] 5.2 On threshold: abort thread, post notification
+- [ ] 5.3 Add SandboxCircuitBreakerMiddleware
+
+## 6. Add sandbox lifecycle management
+
+- [ ] 6.1 Implement 4-case lifecycle: cached→reconnect, creating→reset, missing→create, metadata→reconnect
+
+## 7. Add X-Agent-Flags header support
+
+- [ ] 7.1 Parse X-Agent-Flags header in sidecar proxy
+- [ ] 7.2 Apply per-request flag overrides
+- [ ] 7.3 Add agent-specific flag config in AGENTS.md
+
+## 8. UI: Terminal enhancements
+
+- [ ] 8.1 Show exit code and runtime in terminal footer
+- [ ] 8.2 Show agent attribution
+- [ ] 8.3 Add log search UI with regex
+- [ ] 8.4 Add timeout countdown indicator
+- [ ] 8.5 Add circuit breaker indicator