Implement internationalization support across components

- Integrated `next-intl` for toast messages and locale handling in various components, including `Providers`, `CanvasUserMenu`, and `CreditOverview`.
- Replaced hardcoded strings with translation keys to enhance localization capabilities.
- Updated `RootLayout` to dynamically set the language attribute based on the user's locale.
- Ensured consistent user feedback through localized toast messages in actions such as sign-out, canvas operations, and billing notifications.

convex/export.ts

@@ -44,7 +44,7 @@ export const exportFrame = action({
     });
 
     // Find image/ai-image nodes visually within the frame
-    const imageNodes = allNodes.filter((node) => {
+    const imageNodes = allNodes.filter((node: (typeof allNodes)[number]) => {
       if (node.type !== "image" && node.type !== "ai-image") return false;
       const data = node.data as { storageId?: string };
       if (!data.storageId) return false;