feat: refactor plugin architecture, enhance linting, CI & tooling

- Major refactor of core Fish functions for modularity, caching, and error handling
- Improved `.editorconfig` and Makefile for stricter formatting and linting standards
- Expanded linting support: added EditorConfig checks, auto-install for missing tools, and Makefile targets
- Enhanced CI workflow with clearer permissions and job steps in GitHub Actions
- Updated documentation in `README.md` and `CLAUDE.md` to reflect new features, advanced developer tools, and contribution guidelines
- Improved Node.js version manager detection, switching, and installation logic
- Added/updated utility functions for configuration, silent mode, notifications, and version extraction
- Various bug fixes, code quality improvements, and expanded test coverage

functions/nvm_notify.fish

@@ -8,13 +8,18 @@ function nvm_notify -a message -d "Send notification for Node.js version changes
         return
     end
 
-    # Try different notification methods
-    if command -q osascript # macOS
+    # Try different notification methods until one succeeds
+    if command -q osascript
         osascript -e "display notification \"$message\" with title \"nvm-auto-use\""
-    else if command -q notify-send # Linux
+        return
+    end
+    if command -q notify-send
         notify-send nvm-auto-use "$message"
-    else if command -q terminal-notifier # macOS alternative
+        return
+    end
+    if command -q terminal-notifier
         terminal-notifier -title nvm-auto-use -message "$message"
+        return
     end
 end