perf: Always use bundled CSS (28+ files → 1 file)

- Update head-styles.html to always load bundle.min.css
- Remove development/production conditional CSS loading
- Add CSS auto-rebuild to pre-commit hook
- Track bundle.min.css in git (unignore it)
- Reduces initial CSS requests from 28+ to 1

templates/partials/layout/head-styles.html

@@ -1,10 +1,7 @@
 {{define "head-styles"}}
-    <!-- CSS - Conditional loading: bundled in production, modular in development -->
-    {{if .IsProduction}}
+    <!-- CSS - Always use bundled CSS (built via 'make css-prod') -->
+    <!-- Individual CSS files are merged into one bundle to reduce HTTP requests -->
     <link rel="stylesheet" href="/static/dist/bundle.min.css">
-    {{else}}
-    <link rel="stylesheet" href="/static/css/main.css">
-    {{end}}
     <!-- Print styles - loaded separately, only applied when printing -->
     <link rel="stylesheet" href="/static/css/print.css" media="print">
 {{end}}