Improve OpenCode bridge startup reliability and error handling

[marchingphoenix]

Summary

This PR enhances the OpenCode bridge's startup robustness and error handling by adding a readiness timeout, improving stderr classification, and implementing a connection timeout in the chat participant. These changes ensure the bridge properly waits for process initialization and gracefully handles communication failures.

Key Changes

Bridge Startup & Readiness

• Added waitForReady() method that waits up to 5 seconds for the spawned process to either stabilize or fail, preventing callers from seeing state="idle" when the process is about to crash
• Introduced SPAWN_READY_TIMEOUT_MS constant (5000ms) to define the readiness window
• Added startBridge() test helper that advances fake timers to simulate the readiness timeout

Stderr Handling Improvements

• Refactored handleStderr() to distinguish between genuine errors and informational messages
• Added isStderrError() heuristic that identifies error patterns: "Error:", "ERROR:", "FATAL:", "panic:", "Traceback" (case-insensitive)
• Error-like lines fire error events; other stderr output fires status events with agent: "system" to inform users without terminating responses
• Empty/whitespace-only stderr lines are now ignored

Docker Exec Flag

• Added -i (interactive) flag to docker exec command in in-container execution mode
• Ensured -i is placed after exec but before the container ID

Chat Participant Connection Timeout

• Implemented 30-second connection timeout in handleAsk() that triggers if no events arrive from the bridge
• Timeout is reset on each event, indicating the process is responsive
• Listeners are now registered before sending the prompt to avoid missing early events
• Provides user-friendly error message when timeout occurs

Test Coverage

• Added afterEach() hook to restore real timers after each test
• Added test for early resolution when process errors during startup
• Added tests for -i flag placement in docker exec arguments
• Added comprehensive stderr handling tests covering error patterns, status messages, and empty lines
• Updated all existing tests to use startBridge() helper for consistent timer handling

Implementation Details

• Uses fake timers in tests to control async timing without delays
• The waitForReady() promise settles either via state change listener (error/stopped) or timeout expiration
• Stderr classification uses a regex pattern to catch common error indicators while allowing informational output through
• Connection timeout in chat participant is independent of bridge readiness, providing an additional safety net for hung processes

Version

Bumped to v0.1.4

https://claude.ai/code/session_01D12992HnEWn4Jh3iX9SFRe