fix: Explorer launch and window handling

[cyaiox]

Fix Explorer launch and window handling

Context and scope

The launcher was experiencing issues with the Explorer launch process and window handling, particularly:

1. Inconsistent process startup detection
2. Race conditions between window closing and process initialization
3. Potential analytics events being lost during app quit

Changes

• Added robust process startup verification using process.kill(pid, 0) check
• Improved process monitoring with stdout/stderr capture for better debugging
• Added timeout handling for process startup (10 seconds)
• Separated window closing logic from analytics tracking
• Enhanced error handling and logging during process launch
• Added proper process state tracking with hasStarted flag

Technical details

• Process verification now waits 2 seconds after spawn to ensure stability
• Added proper cleanup of timeouts in all process events
• Improved error messages with specific failure reasons
• Analytics events are now properly tracked in the before-quit event
• Window closing is handled separately to prevent visual flashing

Additional notes

• The timeout values (10s for overall, 2s for stability check) can be adjusted if needed
• Added more detailed logging to help with future debugging
• Process stdout/stderr are now captured for better issue diagnosis