feat(frontend): add dedicated /cli page, nav links, and CTA buttons; remove CLI modals for leaner UX

- New CLI page at /cli with detailed usage and improved Quick Start card header
- Add CLI link to navbars and small ‘Try the CLI’ CTAs on Home & Templates
- Remove CLI modals and unused showCliModal() handler (keep_small_simple)
- Self-host Bootstrap and Font Awesome; add OSI logo and GPL notice in footers
- Dockerfile: verify vendor assets exist at build time
- Minor a11y/contrast and heading-order cleanups (100 a11y)

frontend/static/js/main.js

@@ -337,10 +337,7 @@ function showUploadModal() {
     modal.show();
 }
 
-function showCliModal() {
-    const modal = new bootstrap.Modal(document.getElementById('cliModal'));
-    modal.show();
-}
+
 
 async function validateFile() {
     const fileInput = document.getElementById('fileInput');