feat(editor+trimmer): save output to cloud account via V2 File service

- New /api/files/upload: generic user-scoped Browser→Next→MinIO upload
  (presign → PUT → confirm), 200MB cap, image+video only, returns public URL
- image-editor-export: stageToBlob() + saveStageToCloud(); "Save to my account"
  button in the Image Editor export popover
- Trimmer: "Save to my account" button uploads the trimmed clip blob
- i18n: saveToCloud/savingToCloud/savedToCloud/saveToCloudFailed in fa+en
  (parity 1002/1002)

Connects the two client-side editors to V2 storage — output now lands in the
user's account instead of only a local download.

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

messages/en.json

@@ -671,7 +671,11 @@
       "trimAndCrop": "Trim & Crop",
       "loadingEngine": "Loading FFmpeg engine…",
       "progress": "Progress",
-      "download": "Download {format}"
+      "download": "Download {format}",
+      "saveToCloud": "Save to my account",
+      "savingToCloud": "Saving…",
+      "savedToCloud": "Saved to your account",
+      "saveToCloudFailed": "Could not save"
     },
     "componentsTrimmerTrimmerStrip": {
       "heading": "Trim",
@@ -866,7 +870,11 @@
       "quality": "Quality",
       "download": "Download",
       "canvasNotReady": "Canvas not ready.",
-      "exportStarted": "Export started"
+      "exportStarted": "Export started",
+      "saveToCloud": "Save to my account",
+      "savingToCloud": "Saving…",
+      "savedToCloud": "Saved to your account",
+      "saveToCloudFailed": "Could not save to your account"
     },
     "componentsImageEditorPanelsAdjustPanel": {
       "emptyState": "Open an image to use adjustments.",