Race condition in daemon PID file management

[AgentWOPR]

Bug Description:
In src/cli.ts lines 45-55, there's a race condition between checking if a process exists and cleaning up the PID file. Multiple processes could simultaneously detect a stale PID and try to clean it up.

Location:

• File: src/cli.ts
• Lines: 45-55

Code:

function getDaemonPid(): number | null {
  if (\!existsSync(PID_FILE)) return null;
  const pid = parseInt(readFileSync(PID_FILE, "utf-8").trim());
  try {
    process.kill(pid, 0);
    return pid;
  } catch {
    unlinkSync(PID_FILE);  // Race condition here
    return null;
  }
}

Issues:

1. Race Condition: Multiple processes can try to unlinkSync(PID_FILE) simultaneously
2. TOCTOU Bug: File could be deleted between existsSync and readFileSync
3. Error Handling: parseInt could return NaN for corrupted PID files
4. Signal 0 Limitation: process.kill(pid, 0) doesn't work on Windows

Potential Scenarios:

• Two CLI calls happen simultaneously with stale PID file
• One process deletes PID file while another tries to read it
• Corrupted PID file causes parseInt(NaN) to be passed to process.kill

Recommended Fixes:

1. Add proper error handling for file operations
2. Validate PID before using it
3. Use atomic operations or file locking
4. Handle Windows compatibility

Severity: Low-Medium - Could cause sporadic failures in daemon management