fix: Distributed API UI & metrics polish + DEP0060 suppression

Add Node modal — type selector & state reset:
- Restored a Local/Remote <Select> dropdown in renderFormFields so users can
  explicitly choose the node type instead of it defaulting silently to 'remote'.
- Switching type clears api_url and api_token so no stale remote credentials
  carry over if a user switches from Remote to Local mid-form.
- Replaced the static "Add Remote Node" title with a dynamic one that reflects
  the currently selected type ("Add Local Node" / "Add Remote Node").
- onOpenChange now resets formData to defaultFormData whenever the dialog
  opens, preventing stale values from a previous session leaking in.

Remote connection details — real metrics:
- testRemoteConnection previously returned hard-coded '-' for containers,
  images, and cpus after a successful auth/check ping.
- Now fires three parallel requests (Promise.allSettled) after auth passes:
    /api/stats          → containers total + running count
    /api/system/stats   → cpu.cores
    /api/system/images  → image list length
- Each field falls back to '-' gracefully if an endpoint is unavailable,
  so a slow or older remote instance never breaks the connection test.

DEP0060 util._extend suppression:
- http-proxy@1.18.1 calls util._extend when createProxyServer() is first
  invoked at runtime (NOT at import time). A process.emitWarning override
  placed before the proxy instantiations intercepts only DEP0060 without
  suppressing any other warnings. No package version changes needed.

Also includes linter/formatter normalisation across multiple files.

backend/src/services/DockerController.ts

@@ -350,7 +350,7 @@ class DockerController {
       await container.start();
     } catch (error: any) {
       if (error?.statusCode === 304) {
-        // Container already running — not an error
+        // Container already running - not an error
         return;
       }
       throw error;
@@ -364,7 +364,7 @@ class DockerController {
       await container.stop();
     } catch (error: any) {
       if (error?.statusCode === 304) {
-        // Container already stopped — not an error
+        // Container already stopped - not an error
         return;
       }
       throw error;
@@ -445,7 +445,7 @@ class DockerController {
 
   /**
    * Exec into a container with full session isolation.
-   * All state (exec instance, stream) lives in this closure — no singleton traps.
+   * All state (exec instance, stream) lives in this closure - no singleton traps.
    * The WebSocket message handler is registered here to handle input, resize, and cleanup.
    */
   public async execContainer(containerId: string, ws: WebSocket) {
@@ -516,7 +516,7 @@ class DockerController {
               break;
           }
         } catch {
-          // Non-JSON or malformed message — ignore
+          // Non-JSON or malformed message - ignore
         }
       });