fix(apps): cleanup orphaned app processes on daemon restart

[realkim93]

Summary

• When the daemon restarts, app subprocesses spawned by the previous AppManager remain running as orphans
• The new daemon's AppManager initializes with current_app = None, unaware of these orphans
• Both the orphaned app and the new daemon send commands to the robot simultaneously, causing conflicts

This PR adds _cleanup_orphaned_apps() to AppManager.__init__() that detects and terminates orphaned app processes on startup.

Detection criteria (all must match)

• Executable path is under _get_venv_parent_dir()
• Matches *_venv/bin/python pattern (.venv excluded to protect the daemon itself)
• Command line contains -m (module execution pattern)
• PID is not the current daemon or any of its children

Termination strategy

1. SIGTERM for graceful shutdown (3-second timeout)
2. _kill_process_tree() + kill() for force termination of survivors

Changes

• src/reachy_mini/apps/manager.py: Added _cleanup_orphaned_apps() method + 1-line call in __init__

Test plan

• Start daemon → start an app → restart daemon only → verify orphaned process is cleaned up
• Verify daemon's own process is not falsely terminated
• Verify no errors when no orphaned processes exist

🤖 Generated with Claude Code

[realkim93]

Test Results

Tested locally on macOS (Darwin 25.2.0, Python 3.12.9).

Test 1: Orphaned app process cleanup

• Spawned a fake orphan process (*_venv/bin/python -m http.server) under the venv parent directory, detached from the current process tree via start_new_session=True
• Instantiated AppManager → _cleanup_orphaned_apps() detected and terminated the orphan via SIGTERM
• PASS ✅

Test 2: Daemon self-protection

• Instantiated AppManager and verified the current process (simulating the daemon) was NOT terminated
• .venv exclusion rule correctly protected the daemon's own process
• PASS ✅

Test 3: No orphans — no errors

• Instantiated AppManager with no orphaned processes running
• Initialization completed without errors, current_app correctly set to None
• PASS ✅

Note on second commit

During testing, discovered that psutil.exe() resolves symlinks (e.g., venv/bin/python → /usr/bin/python3.12), which caused the path-based detection to miss orphans. Fixed by also checking cmdline[0], which preserves the original invocation path.