feat: add Essentials [Genre] section to For You tab

Add v2_reco_get_top_genres command that queries the user's most-played
genres from reco_events. Frontend loads top genre and fetches
ideal-discography featured albums filtered by that genre.

src-tauri/src/commands_v2.rs

@@ -4437,6 +4437,28 @@ pub async fn v2_reco_get_forgotten_favorites(
     .await
 }
 
+/// Get user's top genres by play count
+#[tauri::command]
+pub async fn v2_reco_get_top_genres(
+    limit: Option<u32>,
+    reco_state: State<'_, RecoState>,
+) -> Result<Vec<TopGenre>, String> {
+    let guard = reco_state.db.lock().await;
+    let db = guard.as_ref().ok_or("No active session")?;
+    let genres = db.get_top_genre_ids(limit.unwrap_or(5))?;
+    Ok(genres
+        .into_iter()
+        .map(|(id, name)| TopGenre { id, name })
+        .collect())
+}
+
+#[derive(Debug, Clone, serde::Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct TopGenre {
+    pub id: u64,
+    pub name: String,
+}
+
 #[derive(Debug, Clone, serde::Serialize)]
 #[serde(rename_all = "camelCase")]
 pub struct V2LibraryCacheStats {

src-tauri/src/lib.rs

@@ -1387,6 +1387,7 @@ pub fn run() {
             commands_v2::v2_reco_get_home_resolved,
             commands_v2::v2_get_album_suggestions,
             commands_v2::v2_reco_get_forgotten_favorites,
+            commands_v2::v2_reco_get_top_genres,
             commands_v2::v2_library_get_cache_stats,
             commands_v2::v2_library_get_stats,
             commands_v2::v2_library_get_albums,

src-tauri/src/reco_store/db.rs

@@ -425,6 +425,36 @@ impl RecoStoreDb {
         Ok(albums)
     }
 
+    /// Get the user's most-played genres by event count
+    pub fn get_top_genre_ids(&self, limit: u32) -> Result<Vec<(u64, String)>, String> {
+        let mut stmt = self
+            .conn
+            .prepare(
+                r#"
+                SELECT e.genre_id, COALESCE(m.genre_name, ''), COUNT(*) AS play_count
+                FROM reco_events e
+                LEFT JOIN reco_album_meta m ON e.album_id = m.album_id
+                WHERE e.genre_id IS NOT NULL AND e.genre_id > 0
+                GROUP BY e.genre_id
+                ORDER BY play_count DESC
+                LIMIT ?
+                "#,
+            )
+            .map_err(|e| format!("Failed to prepare top genres query: {}", e))?;
+
+        let rows = stmt
+            .query_map(params![limit], |row| {
+                Ok((row.get::<_, u64>(0)?, row.get::<_, String>(1)?))
+            })
+            .map_err(|e| format!("Failed to query top genres: {}", e))?;
+
+        let mut genres = Vec::new();
+        for row in rows {
+            genres.push(row.map_err(|e| format!("Failed to read genre row: {}", e))?);
+        }
+        Ok(genres)
+    }
+
     pub fn get_favorite_track_ids(&self, limit: u32) -> Result<Vec<u64>, String> {
         let mut stmt = self
             .conn