feat: multi-module improvements across merchant, store, i18n, and customer systems

- Fix platform-grouped merchant sidebar menu with core items at root level
- Add merchant store management (detail page, create store, team page)
- Fix store settings 500 error by removing dead stripe/API tab
- Move onboarding translations to module-owned locale files
- Fix onboarding banner i18n with server-side rendering + context inheritance
- Refactor login language selectors to use languageSelector() function (LANG-002)
- Move HTTPException handling to global exception handler in merchant routes (API-003)
- Add language selector to all login pages and portal headers
- Fix customer module: drop order stats from customer model, add to orders module
- Fix admin menu config visibility for super admin platform context
- Fix storefront auth and layout issues
- Add missing i18n translations for onboarding steps (en/fr/de/lb)

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

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

@@ -24,6 +24,7 @@ from app.api.deps import (
 from app.modules.core.utils.page_context import get_store_context
 from app.modules.tenancy.models import User
 from app.templates_config import templates
+from app.utils.i18n import get_jinja2_globals
 
 router = APIRouter()
 
@@ -71,11 +72,13 @@ async def store_login_page(
             url=f"/store/{store_code}/dashboard", status_code=302
         )
 
+    language = getattr(request.state, "language", "fr")
     return templates.TemplateResponse(
         "tenancy/store/login.html",
         {
             "request": request,
             "store_code": store_code,
+            **get_jinja2_globals(language),
         },
     )