- Cap SDK event queue to prevent unbounded growth during high event throughput
- Clean up message parts when trimming excess messages in sync store
- Evict previous session data from memory when switching sessions
- Bound LSP diagnostics map with LRU eviction and clear on shutdown
- Reject pending callbacks on session cancel to prevent promise/closure leaks

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

- Add onCleanup for all sdk.event.on() listeners in app.tsx, session route,
  and prompt component to prevent listener accumulation on re-render
- Add onCleanup for process SIGUSR2 handler in theme provider
- Add onCleanup for leader timeout in keybind provider
- Clear event queue on SDK context cleanup
- Remove empty subscription arrays in Bus and RPC listener maps
- Clear warning timeout in state disposal after completion
- Clear models refresh interval on process exit
- Add dispose() to ShareNext to clear pending sync timeouts
- Clear PTY session buffer on removal to free memory immediately

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Addresses the remaining memory leaks identified in anomalyco#16697 by
consolidating the best fixes from 23+ open community PRs into
a single coherent changeset.

Fixes consolidated from PRs: anomalyco#16695, anomalyco#16346, anomalyco#14650, anomalyco#15646,

- Plugin subscriber stacking: unsub before re-subscribing in init()
- Subagent deallocation: Session.remove() after task completion
- SSE stream cleanup: centralized cleanup with done guard (3 endpoints)
- Compaction data trimming: clear output/attachments on prune
- Process exit cleanup: Instance.disposeAll() with 5s timeout
- Serve cmd: graceful shutdown instead of blocking forever
- Bash tool: ring buffer with 10MB cap instead of O(n²) concat
- LSP index teardown: clear clients/broken/spawning on dispose
- LSP open-files cap: evict oldest when >1000 tracked files
- Format subscription: store and cleanup unsub handle
- Permission/Question clearSession: reject pending on session delete
- Session.remove() cleanup chain: FileTime, Permission, Question
- ShareNext subscription cleanup: store unsub handles, cleanup on dispose
- OAuth transport: close existing before replacing

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Port robust process exit detection from PR anomalyco#15757 to fix zombie/stuck
child processes in containers where Bun fails to deliver exit events.

- Add polling watchdog to bash tool and Process.spawn that detects
  process exit via kill(pid, 0) when event-loop events are missed
- Add process registry (active map) with stale/reap exports for
  server-level watchdog to detect and clean up stuck bash processes
- Improve Shell.killTree with alive() helper and proper SIGKILL
  escalation after SIGTERM timeout
- Add session-level watchdog interval in prompt loop to periodically
  reap stale bash processes

Based on the work in anomalyco#15757.

Co-Authored-By: Nacho F. Lizaur <NachoFLizaur@users.noreply.github.com>

Complete the port of PR anomalyco#15757 with remaining pieces:

- Add stdio end event redundancy as third fallback for exit detection
  (fires when pipe file descriptors close, independent of exit events)
- Add diagnostic log.info calls at spawn, abort, timeout, and each
  exit detection path for debugging container issues
- Add comprehensive tests: defensive patterns, polling watchdog
  isolation, Shell.killTree, server-level watchdog (stale/reap),
  stdio end events, and Process.spawn defensive patterns
- Skip truncation tests on Windows (matching upstream)

Co-Authored-By: Nacho F. Lizaur <NachoFLizaur@users.noreply.github.com>

On Windows, stdio pipe end events can fire before the exit event
populates proc.exitCode, causing it to be null in the result metadata.
Fall back to 0 (or 1 if signalCode is set) when exitCode is null,
matching the same pattern used in Process.spawn.

Co-Authored-By: Nacho F. Lizaur <NachoFLizaur@users.noreply.github.com>