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)

Dockerfile

@@ -28,6 +28,13 @@ WORKDIR /app
 # Copy source code
 COPY . .
 
+# Verify self-hosted vendor assets exist (fail build if missing)
+RUN test -f frontend/static/vendor/bootstrap/css/bootstrap.min.css \
+    && test -f frontend/static/vendor/bootstrap/js/bootstrap.bundle.min.js \
+    && test -f frontend/static/vendor/fontawesome/css/all.min.css \
+    && test -f frontend/static/vendor/fontawesome/webfonts/fa-solid-900.woff2 \
+    && test -f frontend/static/img/osi-logo.svg || (echo 'Missing vendor assets. Ensure static/vendor and images are committed.' && exit 1)
+
 # Install dependencies with uv
 RUN uv venv && \
     uv pip install -e ".[web]"