fix(gateway): handle wmic encoding errors on Windows non-English locales

Pass encoding='utf-8', errors='ignore' and guard against result.stdout
being None so _scan_gateway_pids() no longer crashes with
UnicodeDecodeError + AttributeError on Windows systems whose default
code page is not UTF-8 (e.g. cp936 on zh-CN). The parser only matches
the ASCII prefixes CommandLine= and ProcessId=, so dropping undecodable
bytes is safe.

Closes #17049.

hermes_cli/gateway.py

@@ -279,9 +279,11 @@ def _scan_gateway_pids(exclude_pids: set[int], all_profiles: bool = False) -> li
                 ["wmic", "process", "get", "ProcessId,CommandLine", "/FORMAT:LIST"],
                 capture_output=True,
                 text=True,
+                encoding="utf-8",
+                errors="ignore",
                 timeout=10,
             )
-            if result.returncode != 0:
+            if result.returncode != 0 or result.stdout is None:
                 return []
             current_cmd = ""
             for line in result.stdout.split("\n"):