feat: add Prowlarr integration for manual release search

Add Prowlarr indexer integration (step 1: config + manual search).
Allows searching for comics/ebooks releases on Prowlarr indexers
directly from the series detail page, with download links and
per-volume search for missing books.

- Backend: new prowlarr module with search and test endpoints
- Migration: add prowlarr settings (url, api_key, categories)
- Settings UI: Prowlarr config card with test connection button
- ProwlarrSearchModal: auto-search on open, missing volumes shortcuts
- Fix series.readCount i18n plural parameter on series pages

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

apps/api/src/prowlarr.rs

@@ -0,0 +1,202 @@
+use axum::{extract::State, Json};
+use serde::{Deserialize, Serialize};
+use sqlx::Row;
+use utoipa::ToSchema;
+
+use crate::{error::ApiError, state::AppState};
+
+// ─── Types ──────────────────────────────────────────────────────────────────
+
+#[derive(Deserialize, ToSchema)]
+pub struct ProwlarrSearchRequest {
+    pub series_name: String,
+    pub volume_number: Option<i32>,
+}
+
+#[derive(Serialize, Deserialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ProwlarrRelease {
+    pub guid: String,
+    pub title: String,
+    pub size: i64,
+    pub download_url: Option<String>,
+    pub indexer: Option<String>,
+    pub seeders: Option<i32>,
+    pub leechers: Option<i32>,
+    pub publish_date: Option<String>,
+    pub protocol: Option<String>,
+    pub info_url: Option<String>,
+    pub categories: Option<Vec<ProwlarrCategory>>,
+}
+
+#[derive(Serialize, Deserialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ProwlarrCategory {
+    pub id: i32,
+    pub name: Option<String>,
+}
+
+#[derive(Serialize, ToSchema)]
+pub struct ProwlarrSearchResponse {
+    pub results: Vec<ProwlarrRelease>,
+    pub query: String,
+}
+
+#[derive(Serialize, ToSchema)]
+pub struct ProwlarrTestResponse {
+    pub success: bool,
+    pub message: String,
+    pub indexer_count: Option<i32>,
+}
+
+// ─── Config helper ──────────────────────────────────────────────────────────
+
+#[derive(Deserialize)]
+struct ProwlarrConfig {
+    url: String,
+    api_key: String,
+    categories: Option<Vec<i32>>,
+}
+
+async fn load_prowlarr_config(
+    pool: &sqlx::PgPool,
+) -> Result<(String, String, Vec<i32>), ApiError> {
+    let row = sqlx::query("SELECT value FROM app_settings WHERE key = 'prowlarr'")
+        .fetch_optional(pool)
+        .await?;
+
+    let row = row.ok_or_else(|| ApiError::bad_request("Prowlarr is not configured"))?;
+    let value: serde_json::Value = row.get("value");
+    let config: ProwlarrConfig = serde_json::from_value(value)
+        .map_err(|e| ApiError::internal(format!("invalid prowlarr config: {e}")))?;
+
+    if config.url.is_empty() || config.api_key.is_empty() {
+        return Err(ApiError::bad_request(
+            "Prowlarr URL and API key must be configured in settings",
+        ));
+    }
+
+    let url = config.url.trim_end_matches('/').to_string();
+    let categories = config.categories.unwrap_or_else(|| vec![7030, 7020]);
+
+    Ok((url, config.api_key, categories))
+}
+
+// ─── Handlers ───────────────────────────────────────────────────────────────
+
+/// Search for releases on Prowlarr
+#[utoipa::path(
+    post,
+    path = "/prowlarr/search",
+    tag = "prowlarr",
+    request_body = ProwlarrSearchRequest,
+    responses(
+        (status = 200, body = ProwlarrSearchResponse),
+        (status = 400, description = "Bad request or Prowlarr not configured"),
+        (status = 401, description = "Unauthorized"),
+        (status = 500, description = "Prowlarr connection error"),
+    ),
+    security(("Bearer" = []))
+)]
+pub async fn search_prowlarr(
+    State(state): State<AppState>,
+    Json(body): Json<ProwlarrSearchRequest>,
+) -> Result<Json<ProwlarrSearchResponse>, ApiError> {
+    let (url, api_key, categories) = load_prowlarr_config(&state.pool).await?;
+
+    let query = if let Some(vol) = body.volume_number {
+        format!("\"{}\" {}", body.series_name, vol)
+    } else {
+        format!("\"{}\"", body.series_name)
+    };
+
+    let client = reqwest::Client::builder()
+        .timeout(std::time::Duration::from_secs(30))
+        .build()
+        .map_err(|e| ApiError::internal(format!("failed to build HTTP client: {e}")))?;
+
+    let mut params: Vec<(&str, String)> = vec![
+        ("query", query.clone()),
+        ("type", "search".to_string()),
+    ];
+    for cat in &categories {
+        params.push(("categories", cat.to_string()));
+    }
+
+    let resp = client
+        .get(format!("{url}/api/v1/search"))
+        .query(&params)
+        .header("X-Api-Key", &api_key)
+        .send()
+        .await
+        .map_err(|e| ApiError::internal(format!("Prowlarr request failed: {e}")))?;
+
+    if !resp.status().is_success() {
+        let status = resp.status();
+        let text = resp.text().await.unwrap_or_default();
+        return Err(ApiError::internal(format!(
+            "Prowlarr returned {status}: {text}"
+        )));
+    }
+
+    let results: Vec<ProwlarrRelease> = resp
+        .json()
+        .await
+        .map_err(|e| ApiError::internal(format!("Failed to parse Prowlarr response: {e}")))?;
+
+    Ok(Json(ProwlarrSearchResponse { results, query }))
+}
+
+/// Test connection to Prowlarr
+#[utoipa::path(
+    get,
+    path = "/prowlarr/test",
+    tag = "prowlarr",
+    responses(
+        (status = 200, body = ProwlarrTestResponse),
+        (status = 400, description = "Prowlarr not configured"),
+        (status = 401, description = "Unauthorized"),
+    ),
+    security(("Bearer" = []))
+)]
+pub async fn test_prowlarr(
+    State(state): State<AppState>,
+) -> Result<Json<ProwlarrTestResponse>, ApiError> {
+    let (url, api_key, _categories) = load_prowlarr_config(&state.pool).await?;
+
+    let client = reqwest::Client::builder()
+        .timeout(std::time::Duration::from_secs(10))
+        .build()
+        .map_err(|e| ApiError::internal(format!("failed to build HTTP client: {e}")))?;
+
+    let resp = client
+        .get(format!("{url}/api/v1/indexer"))
+        .header("X-Api-Key", &api_key)
+        .send()
+        .await;
+
+    match resp {
+        Ok(r) if r.status().is_success() => {
+            let indexers: Vec<serde_json::Value> = r.json().await.unwrap_or_default();
+            Ok(Json(ProwlarrTestResponse {
+                success: true,
+                message: format!("Connected successfully ({} indexers)", indexers.len()),
+                indexer_count: Some(indexers.len() as i32),
+            }))
+        }
+        Ok(r) => {
+            let status = r.status();
+            let text = r.text().await.unwrap_or_default();
+            Ok(Json(ProwlarrTestResponse {
+                success: false,
+                message: format!("Prowlarr returned {status}: {text}"),
+                indexer_count: None,
+            }))
+        }
+        Err(e) => Ok(Json(ProwlarrTestResponse {
+            success: false,
+            message: format!("Connection failed: {e}"),
+            indexer_count: None,
+        })),
+    }
+}