Improve performance on poor connections: local assets, gzip, caching

- Replace Tailwind CDN (~350KB) with purged local CSS (~22KB)
- Replace htmx unpkg CDN with local static file
- Add Gzip middleware (standard library, sync.Pool) for all responses
- Add Cache-Control: public, max-age=3600 for /static/* assets
- Reduce status polling interval from 5s to 30s
- Add scripts/build-css.sh for CSS regeneration after template changes
- Document in bible-local/operations.md and history.md

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

package.json

@@ -0,0 +1,5 @@
+{
+  "devDependencies": {
+    "tailwindcss": "^3.4.1"
+  }
+}