feat(crawler): honour CRAWLER_LIMIT in the in-process daemon (0.47.0)

The CLI binary already capped runs at CRAWLER_LIMIT mangas, but the
daemon's RealMetadataPass passed a hardcoded `0` (no cap) to
`pipeline::run_metadata_pass`, so the env var was silently ignored once
the daemon took over the metadata pass.

Adds `manga_limit` to `CrawlerConfig`, reads it from `CRAWLER_LIMIT`
(default 0 = no cap), and threads it through `RealMetadataPass::run`
so a daemon-driven sweep stops at the same boundary as a CLI run.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

backend/src/app.rs

@@ -185,6 +185,7 @@ async fn spawn_crawler_daemon(
             http: http.clone(),
             rate: Arc::clone(&rate),
             start_url: url.clone(),
+            manga_limit: cfg.manga_limit,
             download_allowlist: cfg.download_allowlist.clone(),
             max_image_bytes: cfg.max_image_bytes,
             tor: tor.as_ref().map(Arc::clone),
@@ -252,6 +253,7 @@ struct RealMetadataPass {
     http: reqwest::Client,
     rate: Arc<HostRateLimiters>,
     start_url: String,
+    manga_limit: usize,
     download_allowlist: DownloadAllowlist,
     max_image_bytes: usize,
     tor: Option<Arc<crate::crawler::tor::TorController>>,
@@ -267,7 +269,7 @@ impl MetadataPass for RealMetadataPass {
             &self.http,
             &self.rate,
             &self.start_url,
-            0,
+            self.manga_limit,
             false,
             &self.download_allowlist,
             self.max_image_bytes,

backend/src/config.rs

@@ -119,6 +119,10 @@ pub struct CrawlerConfig {
     pub download_allowlist: DownloadAllowlist,
     /// Hard upper bound on a single image download. Defaults to 32 MiB.
     pub max_image_bytes: usize,
+    /// Max manga detail fetches per metadata pass. `0` means no cap
+    /// (full sweep up to the source's own bound). Sourced from
+    /// `CRAWLER_LIMIT`, mirroring the CLI binary.
+    pub manga_limit: usize,
 }
 
 impl Default for CrawlerConfig {
@@ -145,6 +149,7 @@ impl Default for CrawlerConfig {
             browser: LaunchOptions::headless(),
             download_allowlist: DownloadAllowlist::new(),
             max_image_bytes: DEFAULT_MAX_IMAGE_BYTES,
+            manga_limit: 0,
         }
     }
 }
@@ -267,6 +272,7 @@ impl CrawlerConfig {
             browser: LaunchOptions::from_env(),
             download_allowlist,
             max_image_bytes: env_usize("CRAWLER_MAX_IMAGE_BYTES", DEFAULT_MAX_IMAGE_BYTES),
+            manga_limit: env_usize("CRAWLER_LIMIT", 0),
         })
     }
 }
@@ -340,3 +346,32 @@ fn env_usize(name: &str, default: usize) -> usize {
         .unwrap_or(default)
 }
 
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::sync::Mutex;
+
+    // Serialise env-touching tests so concurrent cargo-test threads don't
+    // race on the process-global env. Re-acquire on poison since a
+    // panicking test still leaves the env in a consistent state for us
+    // (we set/unset within each guard region).
+    static ENV_GUARD: Mutex<()> = Mutex::new(());
+
+    #[test]
+    fn crawler_limit_env_populates_manga_limit() {
+        let _g = ENV_GUARD.lock().unwrap_or_else(|p| p.into_inner());
+        std::env::set_var("CRAWLER_LIMIT", "96");
+        let cfg = CrawlerConfig::from_env().expect("from_env");
+        std::env::remove_var("CRAWLER_LIMIT");
+        assert_eq!(cfg.manga_limit, 96);
+    }
+
+    #[test]
+    fn crawler_limit_unset_defaults_to_zero() {
+        let _g = ENV_GUARD.lock().unwrap_or_else(|p| p.into_inner());
+        std::env::remove_var("CRAWLER_LIMIT");
+        let cfg = CrawlerConfig::from_env().expect("from_env");
+        assert_eq!(cfg.manga_limit, 0);
+    }
+}
+