fix: reliability improvements for async operations

[adolago]

Summary

This PR adds several reliability improvements for async operations in the codebase.

Changes

MCP State Synchronization (mcp/index.ts)

• Added per-server mutex (serverMutexes Map + withServerMutex) to prevent concurrent state mutations for the same server
• Wrapped add, connect, disconnect, and reconnect operations with mutex
• Added transport cleanup on connection failure and for unused pending OAuth transports

LSP Client Cleanup (lsp/client.ts)

• Added connection disposal and server process cleanup on initialization failure
• Prevents resource leaks when LSP server fails to initialize

PTY Subscriber Management (pty/index.ts)

• Added proactive cleanup of stale subscribers (those not in readyState 1) when new client connects
• Added onError handler alongside onClose for WebSocket error handling

Improved Error Logging

• Replaced silent .catch(() => {}) blocks with debug logging in:
  • config/config.ts - Plugin installation errors
  • file/watcher.ts - Subscription cleanup failures
  • project/instance.ts - Instance disposal errors

Testing

These changes have been tested on the agent-core fork and all 721 tests pass.

Motivation

These fixes address:

1. Race conditions - Concurrent MCP server operations could corrupt state
2. Resource leaks - Failed LSP/transport connections weren't being cleaned up
3. Debuggability - Silent catches made it difficult to diagnose issues

[github-actions]

Thanks for your contribution!

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[github-actions]

The following comment was made by an LLM, it may be inaccurate:

The search results show the current PR (#9047) and two other PRs related to memory leak prevention:

Potential Related PRs:

1. fix(core): add dispose functions to prevent subscription memory leaks #7032 - fix(core): add dispose functions to prevent subscription memory leaks

   • Related to resource cleanup and memory leak prevention similar to the current PR's focus on cleaning up failed connections and resources

2. fix(core): add dispose functions to prevent subscription memory leaks #7914 - fix(core): add dispose functions to prevent subscription memory leaks

   • Same title as fix(core): add dispose functions to prevent subscription memory leaks #7032, potentially a duplicate or related to the same issue

These PRs address similar concerns around cleanup and disposal of resources, which aligns with the current PR's work on LSP client cleanup and transport cleanup. However, they appear to be older PRs focused on subscription memory leaks rather than the comprehensive async operation reliability improvements in PR #9047.

The current PR #9047 appears to be a newer, more comprehensive fix that builds on or complements these earlier cleanup efforts.