Add request tracing, debug /v1/keys/list endpoint

- TraceLayer logs every HTTP request (method, path, status, duration)
- Default log level info, tower_http=debug (no RUST_LOG needed)
- GET /v1/keys/list shows all registered fingerprints
- Helps debug key registration and lookup issues

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

warzone/crates/warzone-server/src/routes/keys.rs

@@ -10,9 +10,25 @@ use crate::state::AppState;
 pub fn routes() -> Router<AppState> {
     Router::new()
         .route("/keys/register", post(register_keys))
+        .route("/keys/list", get(list_keys))
         .route("/keys/{fingerprint}", get(get_bundle))
 }
 
+/// Debug endpoint: list all registered fingerprints.
+async fn list_keys(State(state): State<AppState>) -> Json<serde_json::Value> {
+    let keys: Vec<String> = state
+        .db
+        .keys
+        .iter()
+        .filter_map(|item| {
+            item.ok()
+                .and_then(|(k, _)| String::from_utf8(k.to_vec()).ok())
+        })
+        .collect();
+    tracing::info!("Listed {} registered keys", keys.len());
+    Json(serde_json::json!({ "keys": keys, "count": keys.len() }))
+}
+
 /// Normalize fingerprint: strip colons, lowercase.
 fn normalize_fp(fp: &str) -> String {
     fp.chars()