Carry file size, thumbnail size, and deletion flag through decryptFile (closes #37)

decryptFile now sets file.size/thumbnail.size from raw.info (undefined when absent) and carries an optional isDeleted on EnteFile. Plain EnteFile return, no caller changes; listFiles keeps filtering tombstones. Tests cover the three fields and the size-absent case.

Model: opus-4-8

src/model/types.ts

@@ -48,6 +48,9 @@ export interface EnteFile {
     file: FileBlob;
     thumbnail: FileBlob;
     updationTime: Microseconds;
+    // Set from the diff row's flag. Live files decode with it absent/false;
+    // deleted rows are filtered out before decryptFile, so it is not set here.
+    isDeleted?: boolean;
 }
 
 // The key material a logged-in client holds, everything needed to decrypt