fix: set world-writable permissions on cluster log dir and files (#203)

[kaixinbaba]

Root Cause

The cluster worker container runs as the claude-code user, while the host process (in lib/cluster/execute.js) runs as root. When the root process creates the log directory and writes initial files (system-prompt.md, user-prompt.md, meta.json, trigger.json), they are created with restrictive permissions that prevent the worker container from:

• Creating new files in the log directory (stdout.jsonl, stderr.txt)
• Updating existing files (meta.json)

Solution

Added fs.chmodSync() calls to make files and directories world-writable:

1. After fs.mkdirSync(logDir, { recursive: true }) → add fs.chmodSync(logDir, 0o777)
2. After each fs.writeFileSync() for log files → add corresponding fs.chmodSync(filePath, 0o666)

This allows the worker container to read, write, and update all log files without permission errors.

Changed Files

• lib/cluster/execute.js: Added 5 chmodSync calls

Testing

• Syntax check: node --check lib/cluster/execute.js ✓
• Changes are minimal and isolated to log file permissions only