Add better error messages and documentation for cross-distribution compatibility.
**Task 9: System Dependency Checker (scripts/check-system-deps.sh)**
- New script to check system dependencies regardless of distribution
- Detects Python 3.8+, pkg-config, GTK3, PyGObject, PortAudio
- Checks for text injection tools (xdotool, wtype, ydotool)
- Provides distribution-specific installation instructions
- Supports all 10+ distribution families (Ubuntu, Debian, Fedora, Arch, openSUSE, Gentoo, Alpine, Void, Solus, Mageia)
**Task 10: Better Unsupported Distro Message (install.sh)**
- Enhanced error message for unsupported distributions
- References the new dependency checker script
- Provides manual installation options (skip-system-deps, venv install)
- Includes link to project wiki
- Interactive prompt to continue or cancel
**Task 11: Distro Compatibility Documentation (docs/DISTRO_COMPATIBILITY.md)**
- Comprehensive compatibility matrix for supported distros
- Experimental support section with known issues
- Requirements by distribution with exact commands
- Desktop environment compatibility (GNOME, KDE, Xfce, sway, i3, etc.)
- Display server support (X11, Wayland, XWayland)
- Architecture support (x86_64, arm64, armhf, riscv64)
- Testing checklist for new distributions
- Issue reporting guidelines
- Contributing guidelines for compatibility fixes
Part of cross-distribution compatibility improvements (Phase 3 of 5).
Related to #157
