Initial implementation of qobuz-qt

- Rust backend (qobuz-backend static lib): Qobuz API client (reqwest/tokio),
  Symphonia audio decoder, CPAL audio output, extern "C" FFI bridge
- Qt 6 frontend mirroring spotify-qt layout: toolbar with playback controls,
  left library dock, central track list, right search panel
- Auth: email/password login with MD5-signed requests; session token persisted
  via QSettings
- Playback: double-click a track → Rust fetches stream URL → Symphonia decodes
  → CPAL outputs to default audio device
- Dark Fusion palette matching spotify-qt feel

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

rust/src/api/models.rs

@@ -0,0 +1,260 @@
+use serde::{Deserialize, Serialize};
+
+// --- Auth ---
+
+#[derive(Debug, Deserialize, Clone, Serialize)]
+pub struct OAuthDto {
+    pub token_type: Option<String>,
+    pub access_token: Option<String>,
+    pub refresh_token: Option<String>,
+    pub expires_in: Option<i64>,
+}
+
+#[derive(Debug, Deserialize, Serialize)]
+pub struct OAuthLoginResponse {
+    pub status: Option<String>,
+    pub user: Option<UserDto>,
+    pub oauth2: Option<OAuthDto>,
+    pub user_auth_token: Option<String>,
+}
+
+// --- User ---
+
+#[derive(Debug, Deserialize, Clone, Serialize)]
+pub struct UserDto {
+    pub id: Option<i64>,
+    pub login: Option<String>,
+    pub firstname: Option<String>,
+    pub lastname: Option<String>,
+    pub email: Option<String>,
+    pub display_name: Option<String>,
+    pub country_code: Option<String>,
+    pub subscription: Option<SubscriptionDto>,
+}
+
+#[derive(Debug, Deserialize, Clone, Serialize)]
+pub struct SubscriptionDto {
+    pub description: Option<String>,
+    pub end_date: Option<String>,
+    pub is_recurring: Option<bool>,
+    pub offer: Option<String>,
+}
+
+// --- Track ---
+
+#[derive(Debug, Deserialize, Clone, Serialize)]
+pub struct TrackDto {
+    pub id: i64,
+    pub title: Option<String>,
+    pub duration: Option<i64>,
+    pub track_number: Option<i32>,
+    pub album: Option<AlbumDto>,
+    pub performer: Option<ArtistDto>,
+    pub composer: Option<ArtistDto>,
+    pub work: Option<String>,
+    pub media_number: Option<i32>,
+    pub streamable: Option<bool>,
+    pub purchasable: Option<bool>,
+    pub hires: Option<bool>,
+    pub hires_streamable: Option<bool>,
+    pub audio_info: Option<AudioInfoDto>,
+    pub maximum_bit_depth: Option<i32>,
+    pub maximum_sampling_rate: Option<f64>,
+    pub maximum_channel_count: Option<i32>,
+}
+
+#[derive(Debug, Deserialize, Clone, Serialize)]
+pub struct AudioInfoDto {
+    pub replaygain_track_gain: Option<f64>,
+    pub replaygain_track_peak: Option<f64>,
+}
+
+#[derive(Debug, Deserialize, Clone, Serialize)]
+pub struct TrackFileUrlDto {
+    pub track_id: Option<i64>,
+    pub duration: Option<i64>,
+    pub url: Option<String>,
+    pub format_id: Option<i32>,
+    pub mime_type: Option<String>,
+    pub sampling_rate: Option<f64>,
+    pub bit_depth: Option<i32>,
+}
+
+// --- Album ---
+
+#[derive(Debug, Deserialize, Clone, Serialize)]
+pub struct AlbumDto {
+    pub id: Option<String>,
+    pub title: Option<String>,
+    pub artist: Option<ArtistDto>,
+    pub tracks_count: Option<i32>,
+    pub duration: Option<i64>,
+    pub genre: Option<GenreDto>,
+    pub image: Option<ImageDto>,
+    pub label: Option<LabelDto>,
+    pub release_date_original: Option<String>,
+    pub maximum_bit_depth: Option<i32>,
+    pub maximum_sampling_rate: Option<f64>,
+    pub hires_streamable: Option<bool>,
+    pub streamable: Option<bool>,
+    pub tracks: Option<TracksWrapper>,
+}
+
+#[derive(Debug, Deserialize, Clone, Serialize)]
+pub struct TracksWrapper {
+    pub items: Option<Vec<TrackDto>>,
+    pub total: Option<i32>,
+    pub offset: Option<i32>,
+    pub limit: Option<i32>,
+}
+
+// --- Artist ---
+
+#[derive(Debug, Deserialize, Clone, Serialize)]
+pub struct ArtistDto {
+    pub id: Option<i64>,
+    pub name: Option<String>,
+    pub albums_count: Option<i32>,
+    pub image: Option<ImageDto>,
+    pub biography: Option<BiographyDto>,
+}
+
+#[derive(Debug, Deserialize, Clone, Serialize)]
+pub struct BiographyDto {
+    pub content: Option<String>,
+    pub summary: Option<String>,
+}
+
+// --- Genre ---
+
+#[derive(Debug, Deserialize, Clone, Serialize)]
+pub struct GenreDto {
+    pub id: Option<i64>,
+    pub name: Option<String>,
+    pub slug: Option<String>,
+}
+
+// --- Image ---
+
+#[derive(Debug, Deserialize, Clone, Serialize)]
+pub struct ImageDto {
+    pub small: Option<String>,
+    pub thumbnail: Option<String>,
+    pub large: Option<String>,
+    pub back: Option<String>,
+}
+
+// --- Label ---
+
+#[derive(Debug, Deserialize, Clone, Serialize)]
+pub struct LabelDto {
+    pub id: Option<i64>,
+    pub name: Option<String>,
+}
+
+// --- Search ---
+
+#[derive(Debug, Deserialize, Serialize)]
+pub struct SearchCatalogDto {
+    pub query: Option<String>,
+    pub albums: Option<SearchResultItems<AlbumDto>>,
+    pub tracks: Option<SearchResultItems<TrackDto>>,
+    pub artists: Option<SearchResultItems<ArtistDto>>,
+    pub playlists: Option<SearchResultItems<PlaylistDto>>,
+}
+
+#[derive(Debug, Deserialize, Clone, Serialize)]
+pub struct SearchResultItems<T> {
+    pub items: Option<Vec<T>>,
+    pub total: Option<i32>,
+    pub offset: Option<i32>,
+    pub limit: Option<i32>,
+}
+
+// --- Playlist ---
+
+#[derive(Debug, Deserialize, Clone, Serialize)]
+pub struct PlaylistDto {
+    pub id: Option<i64>,
+    pub name: Option<String>,
+    pub tracks_count: Option<i32>,
+    pub duration: Option<i64>,
+    pub description: Option<String>,
+    pub owner: Option<PlaylistOwnerDto>,
+    pub image_rectangle: Option<Vec<String>>,
+    pub tracks: Option<TracksWrapper>,
+}
+
+#[derive(Debug, Deserialize, Clone, Serialize)]
+pub struct PlaylistOwnerDto {
+    pub id: Option<i64>,
+    pub name: Option<String>,
+}
+
+// --- User library ---
+
+#[derive(Debug, Deserialize, Serialize)]
+pub struct UserPlaylistsDto {
+    pub playlists: Option<SearchResultItems<PlaylistDto>>,
+}
+
+#[derive(Debug, Deserialize, Serialize)]
+pub struct FavArtistDto {
+    pub id: Option<i64>,
+    pub name: Option<String>,
+    pub albums_count: Option<i32>,
+    pub image: Option<ImageDto>,
+}
+
+// --- Format ---
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+pub enum Format {
+    Mp3 = 5,
+    Cd = 6,
+    HiRes96 = 7,
+    HiRes192 = 27,
+}
+
+impl Format {
+    pub fn id(self) -> i32 {
+        self as i32
+    }
+
+    pub fn from_id(id: i32) -> Self {
+        match id {
+            5 => Format::Mp3,
+            6 => Format::Cd,
+            7 => Format::HiRes96,
+            27 => Format::HiRes192,
+            _ => Format::Cd,
+        }
+    }
+
+    pub fn label(self) -> &'static str {
+        match self {
+            Format::Mp3 => "MP3 320",
+            Format::Cd => "CD 16-bit",
+            Format::HiRes96 => "Hi-Res 24-bit/96kHz",
+            Format::HiRes192 => "Hi-Res 24-bit/192kHz",
+        }
+    }
+
+    pub fn all() -> &'static [Format] {
+        &[Format::HiRes192, Format::HiRes96, Format::Cd, Format::Mp3]
+    }
+}
+
+// --- QWS ---
+
+#[derive(Debug, Deserialize, Clone, Serialize)]
+pub struct QwsTokenResponse {
+    pub jwt_qws: Option<QwsToken>,
+}
+
+#[derive(Debug, Deserialize, Clone, Serialize)]
+pub struct QwsToken {
+    pub exp: Option<i64>,
+    pub jwt: Option<String>,
+    pub endpoint: Option<String>,
+}