feat(arr): add an env-only Podnapisi URL seam

ARR_PODNAPISI_URL, same shape as the existing tmdb_url seam: a test
harness can point the provider at a wiremock fake without touching
DESIGN.md §10's config surface.

crates/arr-daemon/src/config.rs

@@ -48,6 +48,11 @@ pub const ENV_TRANSLATE_GOOGLE_BASE_URL: &str = "ARR_TRANSLATE_GOOGLE_BASE_URL";
 pub const ENV_TRANSLATE_COMMAND_TEMPLATE: &str = "ARR_TRANSLATE_COMMAND_TEMPLATE";
 pub const ENV_ALASS_PATH: &str = "ARR_ALASS_PATH";
 pub const ENV_FFMPEG_PATH: &str = "ARR_FFMPEG_PATH";
+/// E2E seam only, env-only, same shape as [`ENV_TMDB_URL`]: `None` means
+/// Podnapisi's real address. Kept out of the config file for the same
+/// reason `tmdb_url` is — DESIGN.md §10 has no business exposing a seam that
+/// only a test harness uses.
+pub const ENV_PODNAPISI_URL: &str = "ARR_PODNAPISI_URL";
 
 pub const DEFAULT_BIND_ADDR: &str = "0.0.0.0:7878";
 pub const DEFAULT_DATABASE_PATH: &str = "arr.db";
@@ -167,6 +172,7 @@ pub struct EnvOverrides {
     pub tmdb_url: Option<String>,
     pub jellyfin_url: Option<String>,
     pub jellyfin_api_key: Option<String>,
+    pub podnapisi_url: Option<String>,
     pub ntfy_url: Option<String>,
     pub ntfy_operator_topic: Option<String>,
     pub opensubtitles_api_key: Option<String>,
@@ -203,6 +209,7 @@ impl EnvOverrides {
             tmdb_url: std::env::var(ENV_TMDB_URL).ok(),
             jellyfin_url: std::env::var(ENV_JELLYFIN_URL).ok(),
             jellyfin_api_key: std::env::var(ENV_JELLYFIN_API_KEY).ok(),
+            podnapisi_url: std::env::var(ENV_PODNAPISI_URL).ok(),
             ntfy_url: std::env::var(ENV_NTFY_URL).ok(),
             ntfy_operator_topic: std::env::var(ENV_NTFY_OPERATOR_TOPIC).ok(),
             opensubtitles_api_key: std::env::var(ENV_OPENSUBTITLES_API_KEY).ok(),
@@ -245,6 +252,9 @@ pub struct Config {
     pub tmdb_url: Option<String>,
     pub jellyfin_url: String,
     pub jellyfin_api_key: Option<String>,
+    /// E2E seam only, env-only. `None` means Podnapisi's built-in default
+    /// address; see [`ENV_PODNAPISI_URL`].
+    pub podnapisi_url: Option<String>,
     pub ntfy_url: String,
     /// The operator's ntfy topic (DESIGN.md §9.5) for *needs a decision* and
     /// *broken*. `None` means those two notifications are skipped — there is
@@ -424,6 +434,7 @@ impl Config {
                 .or(file.jellyfin_url)
                 .unwrap_or_else(|| DEFAULT_JELLYFIN_URL.to_string()),
             jellyfin_api_key: env.jellyfin_api_key,
+            podnapisi_url: env.podnapisi_url,
             ntfy_url: env
                 .ntfy_url
                 .or(file.ntfy_url)
@@ -483,6 +494,7 @@ mod tests {
             DEFAULT_SEED_IDLE_LIMIT_MINUTES
         );
         assert_eq!(config.jellyfin_url, DEFAULT_JELLYFIN_URL);
+        assert_eq!(config.podnapisi_url, None);
         assert!(config.tracker_seeding.is_empty());
         assert_eq!(config.ntfy_url, DEFAULT_NTFY_URL);
         assert_eq!(config.ntfy_operator_topic, None);
@@ -675,6 +687,37 @@ alass_path = "/usr/local/bin/alass"
         ));
     }
 
+    /// Same env-only seam as `tmdb_url`, for the same reason: `arr-e2e` needs
+    /// to point Podnapisi at a `wiremock` fake without a live-tracker risk
+    /// creeping into the config file (DESIGN.md §15, §10).
+    #[test]
+    fn podnapisi_url_is_an_env_only_seam() {
+        let config = Config::resolve(EnvOverrides::default()).unwrap();
+        assert_eq!(config.podnapisi_url, None);
+
+        let env = EnvOverrides {
+            podnapisi_url: Some("http://127.0.0.1:9/subtitles".into()),
+            ..EnvOverrides::default()
+        };
+        let config = Config::resolve(env).unwrap();
+        assert_eq!(
+            config.podnapisi_url.as_deref(),
+            Some("http://127.0.0.1:9/subtitles")
+        );
+
+        let dir = tempfile::tempdir().unwrap();
+        let path = dir.path().join("arr.toml");
+        std::fs::write(&path, "podnapisi_url = \"http://127.0.0.1:9/subtitles\"\n").unwrap();
+        let env = EnvOverrides {
+            config_file: Some(path.to_string_lossy().into_owned()),
+            ..EnvOverrides::default()
+        };
+        assert!(matches!(
+            Config::resolve(env),
+            Err(ConfigError::TomlDecode(_))
+        ));
+    }
+
     #[test]
     fn a_secret_in_the_config_file_is_a_parse_error() {
         let dir = tempfile::tempdir().unwrap();

crates/arr-daemon/src/main.rs

@@ -133,6 +133,7 @@ fn api_state(
             config.opensubtitles_api_key.clone(),
             config.opensubtitles_username.clone(),
             config.opensubtitles_password.clone(),
+            config.podnapisi_url.clone(),
         ))
         .with_translation_backends(translators.backends.clone())
         .with_jellyfin(jellyfin)
@@ -541,6 +542,7 @@ fn subtitle_action(
             config.opensubtitles_api_key.clone(),
             config.opensubtitles_username.clone(),
             config.opensubtitles_password.clone(),
+            config.podnapisi_url.clone(),
         ),
         translators.backends.clone(),
         arr_subs::Syncer::new().with_binary(config.alass_path.clone()),
@@ -564,10 +566,17 @@ fn subtitle_providers(
     opensubtitles_api_key: Option<String>,
     username: Option<String>,
     password: Option<String>,
+    podnapisi_url: Option<String>,
 ) -> Vec<std::sync::Arc<dyn arr_subs::Provider>> {
     let mut providers: Vec<std::sync::Arc<dyn arr_subs::Provider>> = Vec::new();
 
-    match arr_subs::Podnapisi::new() {
+    // `podnapisi_url` is the e2e-only seam (`ARR_PODNAPISI_URL`); absent, this
+    // is the real Podnapisi.net.
+    let mut builder = arr_subs::Podnapisi::builder();
+    if let Some(url) = podnapisi_url {
+        builder = builder.base_url(url);
+    }
+    match builder.build() {
         Ok(podnapisi) => providers.push(std::sync::Arc::new(podnapisi)),
         Err(error) => tracing::warn!(%error, "Podnapisi not available"),
     }