docs: update frontend architecture documentation

Update frontend architecture documentation across all three frontends
(admin, vendor, shop) to reflect current implementation:

- Document template inheritance patterns
- Update Alpine.js component usage
- Add CDN fallback strategy references
- Clarify context variable usage
- Update template structure diagrams

Also update base templates with improved comments and organization.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

docs/frontend/admin/architecture.md

@@ -586,9 +586,11 @@ Optimization Techniques:
    • Server-side pagination
    • Load only needed data
 
-5. CDN Assets
-   • Tailwind CSS from CDN
-   • Alpine.js from CDN
+5. CDN Assets with Fallback
+   • Tailwind CSS from CDN (fallback to local)
+   • Alpine.js from CDN (fallback to local)
+   • Works offline and in restricted networks
+   • See: [CDN Fallback Strategy](../cdn-fallback-strategy.md)
 
 6. Initialization Guards
    • Prevent duplicate setups