feat: suppression individuelle de releases dans les available downloads

Ajoute DELETE /available-downloads/:id?release=N pour supprimer une
release spécifique du JSON array (supprime l'entrée série si c'est
la dernière). Bouton trash sur chaque release dans la page downloads.

Corrige aussi le parsing des ranges de volumes sans préfixe sur le
second nombre (T17-23 détecte maintenant T17 à T23).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/api/src/download_detection.rs

@@ -1,4 +1,4 @@
-use axum::{extract::State, Json};
+use axum::{extract::{Path, State}, Json};
 use serde::{Deserialize, Serialize};
 use sqlx::{PgPool, Row};
 use tracing::{info, warn};
@@ -418,6 +418,82 @@ pub async fn get_latest_found(
     Ok(Json(libs.into_values().collect()))
 }
 
+/// Delete an available download entry, or a single release within it.
+///
+/// - Without `?release=N`: deletes the entire series entry.
+/// - With `?release=N`: removes release at index N from the array;
+///   if the array becomes empty, the entire entry is deleted.
+#[utoipa::path(
+    delete,
+    path = "/available-downloads/{id}",
+    tag = "download_detection",
+    params(
+        ("id" = String, Path, description = "Available download ID"),
+        ("release" = Option<usize>, Query, description = "Release index to remove (omit to delete entire entry)"),
+    ),
+    responses(
+        (status = 200, description = "Deleted"),
+        (status = 404, description = "Not found"),
+    ),
+    security(("Bearer" = []))
+)]
+pub async fn delete_available_download(
+    State(state): State<AppState>,
+    Path(id): Path<Uuid>,
+    axum::extract::Query(query): axum::extract::Query<DeleteAvailableQuery>,
+) -> Result<Json<serde_json::Value>, ApiError> {
+    if let Some(release_idx) = query.release {
+        // Remove a single release from the JSON array
+        let row = sqlx::query("SELECT available_releases FROM available_downloads WHERE id = $1")
+            .bind(id)
+            .fetch_optional(&state.pool)
+            .await?
+            .ok_or_else(|| ApiError::not_found("available download not found"))?;
+
+        let releases_json: Option<serde_json::Value> = row.get("available_releases");
+        if let Some(serde_json::Value::Array(mut releases)) = releases_json {
+            if release_idx >= releases.len() {
+                return Err(ApiError::bad_request("release index out of bounds"));
+            }
+            releases.remove(release_idx);
+
+            if releases.is_empty() {
+                sqlx::query("DELETE FROM available_downloads WHERE id = $1")
+                    .bind(id)
+                    .execute(&state.pool)
+                    .await?;
+            } else {
+                sqlx::query(
+                    "UPDATE available_downloads SET available_releases = $1, updated_at = NOW() WHERE id = $2",
+                )
+                .bind(serde_json::Value::Array(releases))
+                .bind(id)
+                .execute(&state.pool)
+                .await?;
+            }
+        } else {
+            return Err(ApiError::not_found("no releases found"));
+        }
+    } else {
+        // Delete the entire entry
+        let result = sqlx::query("DELETE FROM available_downloads WHERE id = $1")
+            .bind(id)
+            .execute(&state.pool)
+            .await?;
+
+        if result.rows_affected() == 0 {
+            return Err(ApiError::not_found("available download not found"));
+        }
+    }
+
+    Ok(Json(serde_json::json!({ "ok": true })))
+}
+
+#[derive(Deserialize)]
+pub struct DeleteAvailableQuery {
+    pub release: Option<usize>,
+}
+
 // ---------------------------------------------------------------------------
 // Background processing
 // ---------------------------------------------------------------------------