fix(ai): use getattr for ctypes.windll cross-platform mypy compliance

ctypes.windll is Windows-only; accessing it directly causes mypy
[attr-defined] errors on Linux CI. Use getattr(ctypes, 'windll', None)
with explicit None check instead of relying solely on try/except.

No runtime behavior change — the AttributeError was already caught.

Author: sunbos

plugins/sqlseed-ai/src/sqlseed_ai/_hardware.py

@@ -51,7 +51,11 @@ class MEMORYSTATUSEX(ctypes.Structure):
 
         stat = MEMORYSTATUSEX()
         stat.dwLength = ctypes.sizeof(stat)
-        ctypes.windll.kernel32.GlobalMemoryStatusEx(ctypes.byref(stat))
+        # ctypes.windll only exists on Windows; use getattr for cross-platform safety
+        windll = getattr(ctypes, "windll", None)
+        if windll is None:
+            return None
+        windll.kernel32.GlobalMemoryStatusEx(ctypes.byref(stat))
         return (
             round(stat.ullTotalPhys / (1024**3), 1),
             round(stat.ullAvailPhys / (1024**3), 1),