Move startup camera test to background thread

Server starts accepting requests immediately instead of blocking on
the camera test. If the camera lock is held by a previous process,
the server is still reachable and will attempt live camera access
on each request independently.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/main.rs

@@ -53,9 +53,12 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
         .unwrap_or(DEFAULT_PORT);
     let config = CameraConfig::from_env();
 
-    // Test camera access at startup (informational only).
+    // Test camera access at startup (informational only, non-blocking).
+    // Server starts immediately; the camera test runs in the background.
+    let startup_config = config.clone();
+    std::thread::spawn(move || {
         println!("Testing camera access...");
-    match test_camera(&config) {
+        match test_camera(&startup_config) {
             Ok((actual_w, actual_h, frame_size)) => {
                 let conditioned_per_frame = (frame_size / CHUNK_SIZE) * 32;
                 let throughput_30fps = conditioned_per_frame * 30;
@@ -76,7 +79,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
             }
             Err(e) => {
                 eprintln!(
-                "Camera error: {}. Requests will fail until camera is available.",
+                    "Camera warning: {}. Requests will fail until camera is available.",
                     e
                 );
                 if e.contains("Lock Rejected") || e.contains("lock") {
@@ -86,6 +89,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
                 }
             }
         }
+    });
 
     let app = Router::new()
         .route("/", get(index))