refactor: rename public routes and templates to platform

Complete the public -> platform naming migration across the codebase.
This aligns with the naming convention where "platform" refers to
the marketing/public-facing pages of the platform itself.

Changes:
- Update all imports from public to platform modules
- Update template references from public/ to platform/
- Update route registrations to use platform prefix
- Update documentation to reflect new naming
- Update test files for platform API endpoints

Files affected:
- app/api/main.py - router imports
- app/modules/*/routes/*/platform.py - route definitions
- app/modules/*/templates/*/platform/ - template files
- app/modules/routes.py - route discovery
- docs/* - documentation updates
- tests/integration/api/v1/platform/ - test files

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/modules/marketplace/templates/marketplace/platform/find-shop.html

@@ -1,6 +1,6 @@
 {# app/modules/marketplace/templates/marketplace/public/find-shop.html #}
 {# Letzshop Vendor Finder Page #}
-{% extends "public/base.html" %}
+{% extends "platform/base.html" %}
 
 {% block title %}{{ _("cms.platform.find_shop.title") }} - Wizamart{% endblock %}
 
@@ -151,7 +151,7 @@ function vendorFinderData() {
             this.result = null;
 
             try {
-                const response = await fetch('/api/v1/public/letzshop-vendors/lookup', {
+                const response = await fetch('/api/v1/platform/letzshop-vendors/lookup', {
                     method: 'POST',
                     headers: { 'Content-Type': 'application/json' },
                     body: JSON.stringify({ url: this.searchQuery })