fix(cli): decode .env as UTF-8 to avoid GBK crash on Windows

Path.read_text() uses the system locale by default. On Windows CN/JP/KR
locales (GBK/CP932/CP949), reading a UTF-8 .env raises UnicodeDecodeError
as soon as it contains any non-ASCII byte (e.g. an em dash).

Pin encoding="utf-8" on every .env read in hermes_cli to match how the
rest of the codebase (load_dotenv at doctor.py:26) already decodes it.

Adds a regression test that monkeypatches Path.read_text to simulate a
GBK locale and asserts 'hermes doctor' no longer raises.

Refs #18637

hermes_cli/doctor.py

@@ -263,8 +263,11 @@ def run_doctor(args):
     if env_path.exists():
         check_ok(f"{_DHH}/.env file exists")
         
-        # Check for common issues
-        content = env_path.read_text()
+        # Check for common issues. Pin encoding to UTF-8 because .env files are
+        # written as UTF-8 everywhere in the codebase, while Path.read_text()
+        # defaults to the system locale — which crashes on non-UTF-8 Windows
+        # locales (e.g. GBK) as soon as the file contains any non-ASCII byte.
+        content = env_path.read_text(encoding="utf-8")
         if _has_provider_env_config(content):
             check_ok("API key or custom endpoint configured")
         else:

hermes_cli/main.py

@@ -289,7 +289,7 @@ def _has_any_provider_configured() -> bool:
     env_file = get_env_path()
     if env_file.exists():
         try:
-            for line in env_file.read_text().splitlines():
+            for line in env_file.read_text(encoding="utf-8").splitlines():
                 line = line.strip()
                 if line.startswith("#") or "=" not in line:
                     continue

hermes_cli/memory_setup.py

@@ -361,7 +361,7 @@ def _write_env_vars(env_path: Path, env_writes: dict) -> None:
 
     existing_lines = []
     if env_path.exists():
-        existing_lines = env_path.read_text().splitlines()
+        existing_lines = env_path.read_text(encoding="utf-8").splitlines()
 
     updated_keys = set()
     new_lines = []