fix: document skip_reason in Plugin docstring; remove unused import in test

hbd/client/plugin.py

@@ -29,6 +29,7 @@ class Plugin(ABC):
         description: Human-readable description
         interval: Collection interval in seconds (0 for InfoPlugin = collect once)
         enabled: Whether plugin is active (can be disabled via config)
+        skip_reason: Optional[str] = None  # Set before returning False from initialize() so loader logs INFO not WARNING
     """
     
     name: str = ""

tests/test_plugin.py

@@ -2,7 +2,7 @@ import asyncio
 import logging
 import textwrap
 
-from hbd.client.plugin import Plugin, PluginLoader, PluginRegistry
+from hbd.client.plugin import PluginLoader, PluginRegistry
 
 
 def test_plugin_skip_reason_defaults_none(tmp_path):