feat: add i18n translations to platform marketing website

- Add platform translation keys to all locale files (en, fr, de, lb)
- Integrate language selector in platform base template header
- Translate homepage-wizamart.html (hero, pricing, addons, find-shop, CTA)
- Translate pricing.html, find-shop.html, signup-success.html
- Add i18n context to platform routes via get_jinja2_globals()
- Support variable interpolation for trial_days, count parameters

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/routes/platform_pages.py

@@ -16,6 +16,7 @@ from sqlalchemy.orm import Session
 
 from app.core.config import settings
 from app.core.database import get_db
+from app.utils.i18n import get_jinja2_globals
 
 router = APIRouter()
 logger = logging.getLogger(__name__)
@@ -28,7 +29,10 @@ templates = Jinja2Templates(directory=str(TEMPLATES_DIR))
 
 def get_platform_context(request: Request, db: Session) -> dict:
     """Build context for platform pages."""
-    return {
+    # Get language from request state (set by middleware)
+    language = getattr(request.state, "language", "fr")
+
+    context = {
         "request": request,
         "platform_name": "Wizamart",
         "platform_domain": settings.platform_domain,
@@ -36,6 +40,11 @@ def get_platform_context(request: Request, db: Session) -> dict:
         "trial_days": settings.stripe_trial_days,
     }
 
+    # Add i18n globals (_, t, current_language, SUPPORTED_LANGUAGES, etc.)
+    context.update(get_jinja2_globals(language))
+
+    return context
+
 
 # =============================================================================
 # Homepage