Add complete configuration override system

✨ NEW FEATURE: Complete file override capability

🎯 Problem Solved:
- No more mixed configuration approaches causing broken symlinks
- Clean separation: either rich config OR manual override
- Complete control over configuration files

🔧 New Options:
- overrides.hyprlandConf: Complete hyprland.conf override
- overrides.quickshellConfig: Complete Config.qml override
- overrides.footConfig: Complete foot.ini override
- overrides.hyprDirectory: Complete directory override
- overrides.quickshellDirectory: Complete directory override

🛡️ Safety Features:
- Warnings when overrides conflict with rich config
- Rich config modules respect override settings
- No file mixing - one approach per file

✅ Use Cases:
- Manual configuration: Set overrides.hyprlandConf
- Rich NixOS config: Use hyprland.* options
- Directory copy: Use overrides.hyprDirectory
- Never mix approaches on same file!

modules/components/quickshell-config.nix

@@ -208,8 +208,8 @@ in
     };
   };
   
-  config = mkIf config.programs.dots-hyprland.enable {
-    # Generate the Config.qml file with NixOS-managed values
+  config = mkIf (config.programs.dots-hyprland.enable && config.programs.dots-hyprland.overrides.quickshellConfig == null) {
+    # Only generate if no manual override is set
     xdg.configFile."quickshell/ii/modules/common/Config.qml".text = ''
       pragma Singleton
       pragma ComponentBehavior: Bound