feat(dashboard): "My Renders" page for users

- /dashboard/renders: user's own render jobs (live status + progress bar + cancel)
  and finished exports (thumbnail + size/duration + download); bilingual fa/en
- server lib my-renders.ts (user-scoped /v1/renders + /v1/exports via session JWT)
- user action routes: POST /api/renders/[id]/cancel, GET /api/exports/[id]/download
  (presigned URL)
- dashboard sidebar: "رندرهای من / My Renders" nav item

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

messages/en.json

@@ -663,7 +663,8 @@
       "templates": "Templates",
       "upgrade": "Upgrade",
       "settings": "Settings",
-      "navLabel": "Dashboard"
+      "navLabel": "Dashboard",
+      "myRenders": "My Renders"
     },
     "componentsDashboardDashboardTopBar": {
       "searchPlaceholder": "Search projects..."
@@ -1226,6 +1227,19 @@
       "savedAsBlog": "Saved as blog post",
       "saveError": "Could not save post",
       "mustConfigure": "Configure and enable OpenAI above before generating."
+    },
+    "componentsDashboardMyRenders": {
+      "title": "My Renders",
+      "subtitle": "Status of your renders and ready-to-download videos.",
+      "processing": "Processing",
+      "ready": "Ready to download",
+      "empty": "No renders yet.",
+      "emptyReady": "No ready videos.",
+      "cancel": "Cancel",
+      "download": "Download",
+      "confirm": "Cancel this render?",
+      "failed": "Failed",
+      "refresh": "Refresh"
     }
   }
 }