Enhance backend idle management and diagnostics in SwarmUI

- Updated the `wait_backend_idle` function to handle disabled backends, introducing a new failure condition and diagnostics collection for better error handling.
- Refactored the `install_swarm_comfy` script to include a new `configure_comfy_backend` function, streamlining backend configuration and enabling better management of backend states.
- Added tests to validate the new functionality for handling disabled backends and ensuring robust diagnostics, improving overall backend management.

tests/test_wait_backend_idle.py

@@ -41,6 +41,10 @@ def test_install_swarm_comfy_script_payload():
     assert 'bstat == "errored"' in text
     assert "sanitize_backends_fds" in text or "recover_empty_backends" in text
     assert "AddNewBackend" in text
+    assert "EditBackend" in text
+    assert "dlbackend/ComfyUI/main.py" in text
+    assert "configure_comfy_backend" in text
+    assert 'bstat in ("empty", "disabled", "all_disabled", "unknown")' in text
 
 
 def test_wait_backend_idle_fail_fast_on_errored(monkeypatch):
@@ -72,6 +76,40 @@ def test_wait_backend_idle_fail_fast_on_errored(monkeypatch):
     assert diag_calls["n"] == 1
 
 
+def test_wait_backend_idle_fail_fast_on_disabled(monkeypatch):
+    from gpu_rent.errors import CloudError
+    from gpu_rent import ready
+
+    class Cfg:
+        pass
+
+    def fake_ssh(*a, **k):
+        return "BUSY backend=disabled"
+
+    diag_calls = {"n": 0}
+
+    def fake_diag(*a, **k):
+        diag_calls["n"] += 1
+        return "DIAG ok"
+
+    monkeypatch.setattr(ready, "run_ssh", fake_ssh)
+    monkeypatch.setattr(ready, "collect_swarm_diagnostics", fake_diag)
+    try:
+        ready.wait_backend_idle(
+            Cfg(),
+            "1.2.3.4",
+            [].append,
+            timeout=600.0,
+            poll_every=0.01,
+            disabled_fail_sec=0.05,
+        )
+        assert False, "expected CloudError"
+    except CloudError as exc:
+        assert "disabled" in str(exc).lower()
+        assert "startscript" in str(exc).lower()
+    assert diag_calls["n"] == 1
+
+
 def test_swarm_diag_script_covers_api_and_journal():
     from importlib.resources import files