feat: enhance install script and theme generation

- install.sh now installs all variants when run without parameters
- preserve single-variant mode when --variant is specified
- add variant names to generated file headers for clarity
- fix tool name extraction to preserve compound names like git-delta
- fix CSS variable preservation during header generation

.serena/memories/suggested-commands.md

@@ -40,7 +40,7 @@ make demo                # Run web demo server
 
 ## Installation & Deployment
 ```bash
-./cli/install.sh         # Deploy all configs to ~/.config (when implemented)
+./install.sh cli         # Deploy CLI configs to ~/.config
 ENGINE=docker ./verify/verify.sh  # Verify in container (when implemented)
 ```