fix(lora): review findings for the LoraManager layout (#355)

- The example-images library subfolder goes through the folder guard like
  its root, so its canonical (normcased) form matches the media check on
  Windows for a library name with capitals.
- A failed trigger-word load is retried by a running node only after
  TRIGGER_RETRY_SECONDS, not on every prompt run.
- A review whose discovery cannot list a folder says so (folder-unreadable,
  the folder's name only) instead of a generic error.

tests/test_node_execution_contract.py

@@ -334,6 +334,24 @@ class TestLoraTriggerWords(NodeTestCase):
         self.assertEqual(text, "a cat <lora:neon:1>")
         self.assertIn("share gone", "\n".join(logs.output))
 
+    def test_a_failed_load_is_not_retried_on_every_run(self):
+        from py import lora_utils
+
+        cache = lora_utils.get_trigger_cache()
+        cache.clear()
+        self.addCleanup(cache.clear)
+        with (
+            mock.patch.dict(sys.modules, {"py.config": fake_integration_config(True)}),
+            mock.patch.object(
+                lora_utils, "discover_sidecars", side_effect=OSError("share gone")
+            ) as discover,
+            mock.patch.object(lora_utils, "default_lora_roots", return_value=[]),
+            self.assertLogs("prompt_manager.lora_utils", level="WARNING"),
+        ):
+            for _ in range(3):
+                self.node._inject_lora_trigger_words("a cat <lora:neon:1>")
+        self.assertEqual(discover.call_count, 1)
+
 
 class TestPromptManagerEncoding(NodeTestCase):
     node_cls = PromptManager