feat: add rest api for music tracks

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/claude-agent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/api/mod.rs

@@ -0,0 +1,86 @@
+use axum::{
+    extract::{Path, Query, State},
+    http::StatusCode,
+    routing::{delete, get, post},
+    Json, Router,
+};
+use serde::Deserialize;
+use uuid::Uuid;
+
+use crate::models::{CreateTrack, Track};
+use crate::AppState;
+
+pub fn routes(state: AppState) -> Router {
+    Router::new()
+        .route("/tracks", get(list_tracks))
+        .route("/tracks", post(create_track))
+        .route("/tracks/:id", get(get_track))
+        .route("/tracks/:id", delete(delete_track))
+        .route("/tracks/search", get(search_tracks))
+        .route("/stats", get(get_stats))
+        .with_state(state)
+}
+
+async fn list_tracks(State(state): State<AppState>) -> Json<Vec<Track>> {
+    let agg = state.read().await;
+    Json(agg.get_all().to_vec())
+}
+
+async fn create_track(
+    State(state): State<AppState>,
+    Json(input): Json<CreateTrack>,
+) -> (StatusCode, Json<Track>) {
+    let mut agg = state.write().await;
+    let track = agg.add_track(input.into());
+    (StatusCode::CREATED, Json(track))
+}
+
+async fn get_track(
+    State(state): State<AppState>,
+    Path(id): Path<Uuid>,
+) -> Result<Json<Track>, StatusCode> {
+    let agg = state.read().await;
+    agg.get_by_id(id)
+        .cloned()
+        .map(Json)
+        .ok_or(StatusCode::NOT_FOUND)
+}
+
+async fn delete_track(
+    State(state): State<AppState>,
+    Path(id): Path<Uuid>,
+) -> StatusCode {
+    let mut agg = state.write().await;
+    if agg.delete(id) {
+        StatusCode::NO_CONTENT
+    } else {
+        StatusCode::NOT_FOUND
+    }
+}
+
+#[derive(Deserialize)]
+struct SearchQuery {
+    artist: String,
+}
+
+async fn search_tracks(
+    State(state): State<AppState>,
+    Query(query): Query<SearchQuery>,
+) -> Json<Vec<Track>> {
+    let agg = state.read().await;
+    Json(agg.search_by_artist(&query.artist).into_iter().cloned().collect())
+}
+
+#[derive(serde::Serialize)]
+struct Stats {
+    track_count: usize,
+    total_duration_secs: u32,
+}
+
+async fn get_stats(State(state): State<AppState>) -> Json<Stats> {
+    let agg = state.read().await;
+    Json(Stats {
+        track_count: agg.get_all().len(),
+        total_duration_secs: agg.total_duration(),
+    })
+}