chore(openspec): drop 9 superseded proposals + 11 stub archive files

Drop 9 batch proposals that are superseded by the boocode-lift-analysis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/proposal.md

@@ -0,0 +1,26 @@
+## Why
+
+BooTerm currently provides basic terminal panes but lacks structured process lifecycle awareness. AI agents don't know when background tasks complete, what processes are running, or which agent spawned which terminal. Adding PTY exit notifications, rich session metadata, sandbox circuit breaker, and X-Agent-Flags header support gives BooTerm production-grade terminal management.
+
+## What Changes
+
+- Add PTY exit notifications from opencode-pty (`<pty_exited>` structured payload with exit code, last output line)
+- Add session metadata for PTY panes (title, description, parent agent, task ID)
+- Add pattern-based log search with offset/limit pagination
+- Add per-session timeouts for runaway process protection
+- Add sandbox circuit breaker from open-swe (consecutive failures → abort thread)
+- Add sandbox lifecycle management (4 cases: cached, creating, missing, metadata-reconnect)
+- Add X-Agent-Flags header support in llama-sidecar (per-agent LLM parameter overrides)
+- Add GitHub proxy pattern for authenticated git operations in sandbox
+
+## Capabilities
+
+### New Capabilities
+- `pty-exit-notifications`: Structured exit payload on process completion
+- `pty-session-metadata`: Title, description, parent agent per terminal pane
+- `pty-log-search`: Pattern-based PTY buffer search with pagination
+- `pty-timeouts`: Per-session runtime limits for process protection
+- `sandbox-circuit-breaker`: Consecutive failure detection and thread abort
+- `sandbox-lifecycle`: Formal sandbox lifecycle management (4 cases)
+- `agent-flags-override`: Per-agent LLM parameter overrides via X-Agent-Flags
+- `sandbox-github-proxy`: Authenticated git operations without storing tokens

openspec/changes/pty-enhancements/tasks.md

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+## 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