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/admin.py

@@ -13,6 +13,7 @@ from fastapi.responses import HTMLResponse
 from sqlalchemy.orm import Session
 
 from app.api.deps import get_db, require_menu_access
+from app.modules.core.utils.page_context import get_admin_context
 from app.modules.enums import FrontendType
 from app.modules.tenancy.models import User
 from app.templates_config import templates
@@ -43,10 +44,7 @@ async def admin_loyalty_programs(
     """
     return templates.TemplateResponse(
         "loyalty/admin/programs.html",
-        {
-            "request": request,
-            "user": current_user,
-        },
+        get_admin_context(request, db, current_user),
     )
 
 
@@ -62,10 +60,7 @@ async def admin_loyalty_analytics(
     """
     return templates.TemplateResponse(
         "loyalty/admin/analytics.html",
-        {
-            "request": request,
-            "user": current_user,
-        },
+        get_admin_context(request, db, current_user),
     )
 
 
@@ -91,11 +86,7 @@ async def admin_loyalty_merchant_detail(
     """
     return templates.TemplateResponse(
         "loyalty/admin/merchant-detail.html",
-        {
-            "request": request,
-            "user": current_user,
-            "merchant_id": merchant_id,
-        },
+        get_admin_context(request, db, current_user, merchant_id=merchant_id),
     )
 
 
@@ -116,11 +107,7 @@ async def admin_loyalty_program_edit(
     """
     return templates.TemplateResponse(
         "loyalty/admin/program-edit.html",
-        {
-            "request": request,
-            "user": current_user,
-            "merchant_id": merchant_id,
-        },
+        get_admin_context(request, db, current_user, merchant_id=merchant_id),
     )
 
 
@@ -141,9 +128,5 @@ async def admin_loyalty_merchant_settings(
     """
     return templates.TemplateResponse(
         "loyalty/admin/merchant-settings.html",
-        {
-            "request": request,
-            "user": current_user,
-            "merchant_id": merchant_id,
-        },
+        get_admin_context(request, db, current_user, merchant_id=merchant_id),
     )