Consolidate build system and add JS minification (fixes BUG-084)

- Removed dead code: templates/pages/ directory and scripts/build-pages.js
- Updated build:pages script to use build-html.cjs (the actual build used by Dockerfile)
- JS minification now integrated into build-html.cjs for app.js and status.js
- HTML files already reference .min.js files
- Eliminates dual build system that caused deployment confusion

package.json

@@ -4,7 +4,7 @@
   "description": "Markdown/HTML to PDF API with built-in invoice templates",
   "main": "dist/index.js",
   "scripts": {
-    "build:pages": "node scripts/build-pages.js && npx terser public/app.js -o public/app.min.js --compress --mangle",
+    "build:pages": "node scripts/build-html.cjs",
     "build": "node scripts/generate-openapi.mjs && npm run build:pages && tsc",
     "start": "node dist/index.js",
     "dev": "tsx src/index.ts",