fix(crawler): unhang shutdown on lingering Arc<Browser>, silence WS noise (0.43.1)

- Handle::close aborts its chromiumoxide driver task when another
  Arc<Browser> outlives the call, so shutdown returns instead of
  hanging on a stream that never terminates. Generic close_or_abort
  helper with regression tests covering both Arc paths.
- daemon.shutdown() is wrapped in a 5s timeout in main as defense
  in depth.
- Default RUST_LOG silences chromiumoxide::conn / chromiumoxide::handler
  WS-deserialize ERROR spam.

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

backend/src/main.rs

@@ -1,12 +1,21 @@
 use std::net::SocketAddr;
+use std::time::Duration;
 use tracing_subscriber::EnvFilter;
 
+/// Upper bound on how long we're willing to wait for the crawler daemon
+/// to drain before letting `main` return. Without it a wedged background
+/// task (e.g. a chromiumoxide handler stuck on a dead WS) blocks the
+/// process from exiting after Ctrl-C / SIGTERM.
+const CRAWLER_SHUTDOWN_TIMEOUT: Duration = Duration::from_secs(5);
+
 #[tokio::main]
 async fn main() -> anyhow::Result<()> {
     dotenvy::dotenv().ok();
     tracing_subscriber::fmt()
         .with_env_filter(
-            EnvFilter::try_from_default_env().unwrap_or_else(|_| "info,mangalord=debug".into()),
+            EnvFilter::try_from_default_env().unwrap_or_else(|_| {
+                "info,mangalord=debug,chromiumoxide::conn=off,chromiumoxide::handler=off".into()
+            }),
         )
         .init();
 
@@ -21,9 +30,18 @@ async fn main() -> anyhow::Result<()> {
         .await?;
 
     // Drain background tasks (crawler daemon) before exiting so Chromium
-    // gets a clean shutdown rather than relying on kill-on-drop.
+    // gets a clean shutdown rather than relying on kill-on-drop. Bounded
+    // by a timeout so a wedged shutdown path can't trap the process.
     if let Some(d) = daemon {
-        d.shutdown().await;
+        if tokio::time::timeout(CRAWLER_SHUTDOWN_TIMEOUT, d.shutdown())
+            .await
+            .is_err()
+        {
+            tracing::warn!(
+                timeout_s = CRAWLER_SHUTDOWN_TIMEOUT.as_secs(),
+                "crawler daemon shutdown exceeded timeout; abandoning"
+            );
+        }
     }
     Ok(())
 }