feat(marketing): user profile update, ad placement management, logo limits

- Add PUT /auth/profile endpoint for nickname and avatar updates
- Add ad_placements table and CRUD admin API for managing ad units
- Add GET /marketing/ad-config public API for mini-program to fetch ad config
- Reduce logo limit from 10 to 3 per user, add 2MB file size validation

Made-with: Cursor

internal/routes/marketing_routes.go

@@ -14,6 +14,7 @@ func registerMarketingRoutes(
 	templateHandler *marketinghandler.TemplateHandler,
 	downloadHandler *marketinghandler.DownloadHandler,
 	userLogoHandler *marketinghandler.UserLogoHandler,
+	adPlacementHandler *marketinghandler.AdPlacementHandler,
 ) {
 	if categoryHandler == nil || templateHandler == nil || downloadHandler == nil {
 		return
@@ -24,6 +25,10 @@ func registerMarketingRoutes(
 		marketing.GET("/categories", categoryHandler.ListEnabled)
 		marketing.GET("/templates", templateHandler.ListEnabled)
 		marketing.GET("/templates/:id", templateHandler.GetDetail)
+
+		if adPlacementHandler != nil {
+			marketing.GET("/ad-config", adPlacementHandler.GetAdConfig)
+		}
 	}
 
 	protectedMarketing := protected.Group("/marketing")