docs: sync CHANGELOG and OpenAPI with actual implementation

- Fix CHANGELOG: add missing versions v0.2.4-v0.2.12
- Implement GET /v2/_catalog endpoint for Docker repository listing
- Add missing OpenAPI endpoints:
  - Docker: PUT manifest, POST/PATCH/PUT blob uploads, HEAD blob
  - Maven: PUT artifact upload
  - Cargo: GET metadata, GET download (was completely undocumented)
  - Metrics: GET /metrics
- Update OpenAPI version to 0.2.12

nora-registry/src/registry/docker.rs

@@ -47,6 +47,7 @@ static UPLOAD_SESSIONS: std::sync::LazyLock<RwLock<HashMap<String, Vec<u8>>>> =
 pub fn routes() -> Router<Arc<AppState>> {
     Router::new()
         .route("/v2/", get(check))
+        .route("/v2/_catalog", get(catalog))
         // Single-segment name routes (e.g., /v2/alpine/...)
         .route("/v2/{name}/blobs/{digest}", head(check_blob))
         .route("/v2/{name}/blobs/{digest}", get(download_blob))
@@ -87,6 +88,26 @@ async fn check() -> (StatusCode, Json<Value>) {
     (StatusCode::OK, Json(json!({})))
 }
 
+/// List all repositories in the registry
+async fn catalog(State(state): State<Arc<AppState>>) -> Json<Value> {
+    let keys = state.storage.list("docker/").await;
+
+    // Extract unique repository names from paths like "docker/{name}/manifests/..."
+    let mut repos: Vec<String> = keys
+        .iter()
+        .filter_map(|k| {
+            k.strip_prefix("docker/")
+                .and_then(|rest| rest.split('/').next())
+                .map(String::from)
+        })
+        .collect();
+
+    repos.sort();
+    repos.dedup();
+
+    Json(json!({ "repositories": repos }))
+}
+
 async fn check_blob(
     State(state): State<Arc<AppState>>,
     Path((name, digest)): Path<(String, String)>,