Merge pull request #589 with lossless replacement safeguards

Keep automatic Hi-Res replacement off by default. Require exact full-duration PCM equivalence across every channel before and after processing. Retain the original through publication and history persistence, restore it on failure or cancellation, and bound WAV format parsing.

Validated with 30 Rust tests, 46 Dart tests, clean analyzer/Clippy checks, Android ARM64 and iOS builds, and iOS simulator startup.

lib/services/platform_bridge.dart

@@ -1156,6 +1156,18 @@ class PlatformBridge {
     });
   }
 
+  /// Runs the Rust Hi-Res check (spectral cutoff + padded bit depth) on
+  /// a FLAC or WAV file. Returns `{"supported": false}` for other formats.
+  static Future<Map<String, dynamic>> checkHiResAuthenticity(
+    String filePath, {
+    Map<String, dynamic>? options,
+  }) {
+    return _invokeMap('checkHiResAuthenticity', {
+      'file_path': filePath,
+      'options_json': options == null ? '' : jsonEncode(options),
+    });
+  }
+
   /// Reads the tags and quality fields used for automatic Library display.
   ///
   /// Android's readAudioMetadata implementation can inspect most SAF files