fix(i18n): convert remaining $t() to server-side _() and fix store dashboard language

- Convert storefront enrollment $t() calls to server-side _() to silence
  dev-toolbar warnings (welcome bonus + join button)
- Fix store base template I18n.init() to use current_language (from middleware)
  instead of dashboard_language (hardcoded store config) so language changes
  take effect immediately
- Switch admin loyalty routes to use get_admin_context() for proper i18n support
- Switch store loyalty routes to use core get_store_context() from page_context
- Pass program object to storefront enrollment context for server-side rendering
- Add LANG-011 architecture rule: enforce $t()/_() over I18n.t() in templates
- Fix duplicate file_pattern key in LANG-004 rule (YAML validation error)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/modules/loyalty/routes/pages/store.py

@@ -24,10 +24,8 @@ from app.api.deps import (
     get_db,
     get_resolved_store_code,
 )
-from app.modules.core.services.platform_settings_service import (
-    platform_settings_service,
-)
-from app.modules.tenancy.models import Store, User
+from app.modules.core.utils.page_context import get_store_context
+from app.modules.tenancy.models import User
 from app.templates_config import templates
 
 logger = logging.getLogger(__name__)
@@ -42,49 +40,6 @@ ROUTE_CONFIG = {
 }
 
 
-# ============================================================================
-# HELPER: Build Store Context
-# ============================================================================
-
-
-def get_store_context(
-    request: Request,
-    db: Session,
-    current_user: User,
-    store_code: str,
-    **extra_context,
-) -> dict:
-    """Build template context for store loyalty pages."""
-    # Load store from database
-    store = db.query(Store).filter(Store.subdomain == store_code).first()
-
-    # Get platform defaults
-    platform_config = platform_settings_service.get_storefront_config(db)
-
-    # Resolve with store override
-    storefront_locale = platform_config["locale"]
-    storefront_currency = platform_config["currency"]
-
-    if store and store.storefront_locale:
-        storefront_locale = store.storefront_locale
-
-    context = {
-        "request": request,
-        "user": current_user,
-        "store": store,
-        "store_code": store_code,
-        "storefront_locale": storefront_locale,
-        "storefront_currency": storefront_currency,
-        "dashboard_language": store.dashboard_language if store else "en",
-    }
-
-    # Add any extra context
-    if extra_context:
-        context.update(extra_context)
-
-    return context
-
-
 # ============================================================================
 # LOYALTY ROOT (Redirect to Terminal)
 # ============================================================================