fix(storage): make Blossom actually usable in the upload modal [LOCAL] (#30)

Two root causes for "Blossom set as default but not showing / not usable":

1. SAVE required unlock. saveConnection throws "Storage is locked" without a
   master key — but Blossom has no secret. Added
   storageService.saveKeylessConnection() (writes plaintext meta, no encryption,
   no unlock) and the Blossom save branch now uses it. So a Blossom connection
   saves even if the user never unlocked storage.

2. UploadModal treated Blossom like a locked S3 connection: it only set
   activeCredentials when isStorageUnlocked, showed "Locked 🔒", blocked the
   file-pick behind an unlock prompt, and mislabeled it "S3 Compatible". Now:
   getProviderLabel → "Blossom"; loadFromStorage resolves servers from the
   plaintext meta (no unlock); the summary shows "N servers / Nostr-native"; the
   two upload gates and updateLockUi bypass unlock for Blossom
   (activeProviderIsBlossom). Uploads authorize with the Nostr signer instead.

Bumped UploadModal size baseline (+gating code). Lint + build clean. Local only.

Co-Authored-By: Claude Opus 4.8 <[email protected]>

scripts/check-file-size.mjs

@@ -57,7 +57,7 @@ const GRANDFATHERED = {
   "js/app/playbackCoordinator.js": 1376,
   "js/feedEngine/stages.js": 1370,
   "js/ui/views/VideoListView.js": 1359,
-  "js/ui/components/UploadModal.js": 1319,
+  "js/ui/components/UploadModal.js": 1345,
   "js/ui/components/SimilarContentCard.js": 1303,
   "js/services/playbackService.js": 1274,
   "js/services/authService.js": 1335,