refactor: move loose test files out of project root

- tests/test_threshold.py: has proper pytest test functions
- scripts/test_*.py: manual run scripts with no test functions

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

scripts/test_plugins_manual.py

@@ -0,0 +1,60 @@
+#!/usr/bin/env python3
+"""
+Debug plugin loading.
+"""
+
+import asyncio
+import logging
+from pathlib import Path
+
+# Setup path
+import sys
+sys.path.insert(0, str(Path(__file__).parent))
+
+from hbd.plugin import PluginRegistry, PluginLoader
+
+logging.basicConfig(
+    level=logging.DEBUG,
+    format="%(asctime)s %(name)s %(levelname)s: %(message)s"
+)
+
+async def test_manual_load():
+    """Test manual plugin loading."""
+    print("Testing manual plugin import...")
+    
+    # Import plugins directly
+    from hbd.plugins.os_info import OSInfoPlugin
+    from hbd.plugins.cpu_monitor import CPUMonitorPlugin
+    
+    # Create instances
+    os_plugin = OSInfoPlugin()
+    cpu_plugin = CPUMonitorPlugin()
+    
+    print(f"OS Plugin: {os_plugin.name} v{os_plugin.version}")
+    print(f"CPU Plugin: {cpu_plugin.name} v{cpu_plugin.version}")
+    
+    # Initialize
+    print("\nInitializing plugins...")
+    os_init = await os_plugin.initialize()
+    cpu_init = await cpu_plugin.initialize()
+    
+    print(f"OS plugin initialized: {os_init}")
+    print(f"CPU plugin initialized: {cpu_init}")
+    
+    # Collect data
+    if os_init:
+        print("\nCollecting OS info...")
+        os_data = await os_plugin.collect()
+        print(f"Got {len(os_data)} fields:")
+        for k, v in list(os_data.items())[:10]:
+            print(f"  {k}: {v}")
+    
+    if cpu_init:
+        print("\nCollecting CPU info...")
+        cpu_data = await cpu_plugin.collect()
+        print(f"Got {len(cpu_data)} fields:")
+        for k, v in cpu_data.items():
+            print(f"  {k}: {v}")
+
+if __name__ == "__main__":
+    asyncio.run(test_manual_load())