Test: Finder file open (#16)

[hybridmachine]

Testing Plan — Finder File Open (#16)

PR #59 · Parent: #60

• Build the app bundle (cmake --build . --target MacOSNotePP_package)
• Double-click a .txt file in Finder with MacNote++ as handler → file opens
• Right-click file → Open With → MacNote++ → file opens
• From Terminal: open -a "MacNote++" file1.txt file2.txt → both files open
• From Terminal: ./MacOSNotePP /path/to/file.txt → file opens at launch
• Open a file that's already in a tab → switches to existing tab, no duplicate
• App in background, open file from Finder → app comes to front
• Drag file onto Dock icon → opens (regression check from Phase 7)
• Pass a directory path → ignored, no crash