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>

main.py

@@ -64,7 +64,7 @@ from app.exceptions.handler import setup_exception_handlers
 # Module route auto-discovery - all page routes now come from modules
 from app.modules.routes import (
     get_admin_page_routes,
-    get_public_page_routes,
+    get_platform_page_routes,
     get_storefront_page_routes,
     get_vendor_page_routes,
 )
@@ -323,18 +323,18 @@ logger.info("ROUTE REGISTRATION (AUTO-DISCOVERY)")
 logger.info("=" * 80)
 
 # =============================================================================
-# PUBLIC PAGES (Marketing pages - homepage, pricing, signup, etc.)
+# PLATFORM PAGES (Marketing pages - homepage, pricing, signup, etc.)
 # =============================================================================
-# Public pages are served at root level (/) for platform marketing
-logger.info("Auto-discovering public (marketing) page routes...")
-public_page_routes = get_public_page_routes()
-logger.info(f"  Found {len(public_page_routes)} public page route modules")
+# Platform pages are served at root level (/) for platform marketing
+logger.info("Auto-discovering platform (marketing) page routes...")
+platform_page_routes = get_platform_page_routes()
+logger.info(f"  Found {len(platform_page_routes)} platform page route modules")
 
-for route_info in public_page_routes:
-    logger.info(f"  Registering {route_info.module_code} public pages (priority={route_info.priority})")
+for route_info in platform_page_routes:
+    logger.info(f"  Registering {route_info.module_code} platform pages (priority={route_info.priority})")
     app.include_router(
         route_info.router,
-        prefix="",  # Public pages at root
+        prefix="",  # Platform pages at root
         tags=route_info.tags,
         include_in_schema=route_info.include_in_schema,
     )