feat(streaming): CMAF segmented download pipeline

Download tracks via Qobuz Akamai CDN with encrypted CMAF segments.
Derives session key (HKDF), unwraps content key (AES-CBC), decrypts
frames (AES-CTR), reassembles into standard FLAC. Falls back to legacy
track/getFileUrl if CMAF fails.

- Add qbz-cmaf dependency to src-tauri
- Make ensure_cmaf_session public on QobuzClient
- Add ensure_cmaf_session and get_file_url passthroughs to CoreBridge
- Add download_audio_cmaf and try_cmaf_download helpers
- Wire CMAF as primary download path in v2_play_track with legacy fallback

cc

src-tauri/Cargo.lock

@@ -587,6 +587,15 @@ dependencies = [
  "generic-array",
 ]
 
+[[package]]
+name = "block-padding"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a8894febbff9f758034a5b8e12d87918f56dfc64a8e1fe757d65e29041538d93"
+dependencies = [
+ "generic-array",
+]
+
 [[package]]
 name = "block2"
 version = "0.6.2"
@@ -730,6 +739,15 @@ dependencies = [
  "toml 0.9.12+spec-1.1.0",
 ]
 
+[[package]]
+name = "cbc"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "26b52a9543ae338f279b96b0b9fed9c8093744685043739079ce85cd58f289a6"
+dependencies = [
+ "cipher",
+]
+
 [[package]]
 name = "cc"
 version = "1.2.56"
@@ -1353,6 +1371,7 @@ checksum = "9ed9a281f7bc9b7576e61468ba615a66a5c8cfdff42420a70aa82701a3b1e292"
 dependencies = [
  "block-buffer",
  "crypto-common",
+ "subtle",
 ]
 
 [[package]]
@@ -2466,6 +2485,24 @@ version = "0.4.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7f24254aa9a54b5c858eaee2f5bccdb46aaf0e486a595ed5fd8f86ba55232a70"
 
+[[package]]
+name = "hkdf"
+version = "0.12.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7b5f8eb2ad728638ea2c7d47a21db23b7b58a72ed6a38256b8a1849f15fbbdf7"
+dependencies = [
+ "hmac",
+]
+
+[[package]]
+name = "hmac"
+version = "0.12.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6c49c37c09c17a53d937dfbb742eb3a961d65a994e6bcdcf37e7399d0cc8ab5e"
+dependencies = [
+ "digest",
+]
+
 [[package]]
 name = "home"
 version = "0.5.12"
@@ -2851,6 +2888,7 @@ version = "0.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "879f10e63c20629ecabbb64a8010319738c66a5cd0c29b02d63d272b03751d01"
 dependencies = [
+ "block-padding",
  "generic-array",
 ]
 
@@ -4676,6 +4714,21 @@ dependencies = [
  "tokio",
 ]
 
+[[package]]
+name = "qbz-cmaf"
+version = "0.1.0"
+dependencies = [
+ "aes",
+ "base64 0.22.1",
+ "cbc",
+ "ctr",
+ "hkdf",
+ "log",
+ "md-5",
+ "sha2",
+ "thiserror 2.0.18",
+]
+
 [[package]]
 name = "qbz-core"
 version = "0.1.0"
@@ -4767,6 +4820,7 @@ dependencies = [
  "qbz-audio",
  "qbz-cache",
  "qbz-cast",
+ "qbz-cmaf",
  "qbz-core",
  "qbz-integrations",
  "qbz-library",
@@ -4838,6 +4892,7 @@ dependencies = [
  "futures-util",
  "log",
  "md-5",
+ "qbz-cmaf",
  "qbz-models",
  "regex",
  "reqwest 0.12.28",