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/core/utils/__init__.py

@@ -5,12 +5,12 @@ from .page_context import (
     get_admin_context,
     get_vendor_context,
     get_storefront_context,
-    get_public_context,
+    get_platform_context,
 )
 
 __all__ = [
     "get_admin_context",
     "get_vendor_context",
     "get_storefront_context",
-    "get_public_context",
+    "get_platform_context",
 ]

app/modules/core/utils/page_context.py

@@ -253,13 +253,13 @@ def get_storefront_context(
     return context
 
 
-def get_public_context(
+def get_platform_context(
     request: Request,
     db: Session,
     **extra_context,
 ) -> dict:
     """
-    Build context for public/marketing pages.
+    Build context for platform/marketing pages.
 
     Includes platform info, i18n globals, and CMS navigation pages.