Add Hi-Res authenticity check

Introduce a per-file Hi-Res authenticity checker and optional auto re-download for flagged fake Hi-Res downloads. Adds Rust checker modules (fft, evidence, FLAC/WAV decoding, tests) and a mobile API (check_hires_authenticity). Wire platform bindings for Android/iOS and PlatformBridge. Add Dart HiResCheckService, UI HiResCheckCard, settings toggle (redownloadFakeHiRes) and integration in the download pipeline to quarantine and replace suspicious files with LOSSLESS when safe. Adds claxon FLAC dependency.

rust_backend/Cargo.lock

@@ -474,6 +474,12 @@ version = "1.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1c133bc6a41be0d194c306b5506d15e6feeea7b1d6604bd3f8310dfb2ca96486"
 
+[[package]]
+name = "claxon"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4bfbf56724aa9eca8afa4fcfadeb479e722935bb2a0900c2d37e0cc477af0688"
+
 [[package]]
 name = "cmov"
 version = "0.5.4"
@@ -2366,6 +2372,7 @@ version = "0.1.0"
 dependencies = [
  "base64",
  "chrono",
+ "claxon",
  "image",
  "regex",
  "rustix",