feat: Add CSS bundling with Lightning CSS for production optimization

- Add Lightning CSS integration for CSS bundling and minification
- Create Makefile targets: css-dev, css-prod, css-watch, css-clean
- Implement conditional CSS loading based on GO_ENV (dev=modular, prod=bundled)
- Add IsProduction template variable for environment-aware rendering
- Keep print.css separate with media="print" for PDF export
- Add static/dist/ to .gitignore (generated bundles)
- Fix Go template syntax in _cv-header.css
- Remove redundant font @import in _typography.css

Performance gains:
- 27 HTTP requests → 1 (96% reduction)
- 188KB → 86KB CSS (54% reduction)
- ~15KB gzip network transfer

Documentation:
- Update 12-CSS-ARCHITECTURE.md with bundling section
- Add Phase 9 to 2-MODERN-WEB-TECHNIQUES.md
- Add css-bundling.test.mjs Playwright test (8/8 pass)

static/css/01-foundation/_typography.css

@@ -2,8 +2,7 @@
    TYPOGRAPHY - Fonts & Text Styles
    ============================================================================ */
 
-/* Font Imports */
-@import url('https://fonts.googleapis.com/css2?family=Quicksand:wght@400;500;600;700&family=Source+Sans+Pro:wght@400;600&family=Inter:wght@400;500;600;700&display=swap');
+/* NOTE: Fonts are loaded via <link> in index.html for better performance */
 
 /* Base Typography */
 body {

static/css/03-components/_cv-header.css

@@ -41,7 +41,7 @@
     font-family: 'Quicksand', sans-serif;
     font-size: 2.2em;
     font-weight: 400;
-    {{/* font-style: italic; */}}
+    /* font-style: italic; */
     line-height: 1.1;
     margin-bottom: 8px;
     color: var(--text-primary);