chore: remove duplicate dead _try_gh_cli_token / _gh_cli_candidates from auth.py

These functions were duplicated between auth.py and copilot_auth.py.
The auth.py copies had zero production callers — only copilot_auth.py's
versions are used. Redirect the test import to the live copy and update
monkeypatch targets accordingly.

hermes_cli/auth.py

@@ -308,44 +308,6 @@ def _resolve_kimi_base_url(api_key: str, default_url: str, env_override: str) ->
     return default_url
 
 
-def _gh_cli_candidates() -> list[str]:
-    """Return candidate ``gh`` binary paths, including common Homebrew installs."""
-    candidates: list[str] = []
-
-    resolved = shutil.which("gh")
-    if resolved:
-        candidates.append(resolved)
-
-    for candidate in (
-        "/opt/homebrew/bin/gh",
-        "/usr/local/bin/gh",
-        str(Path.home() / ".local" / "bin" / "gh"),
-    ):
-        if candidate in candidates:
-            continue
-        if os.path.isfile(candidate) and os.access(candidate, os.X_OK):
-            candidates.append(candidate)
-
-    return candidates
-
-
-def _try_gh_cli_token() -> Optional[str]:
-    """Return a token from ``gh auth token`` when the GitHub CLI is available."""
-    for gh_path in _gh_cli_candidates():
-        try:
-            result = subprocess.run(
-                [gh_path, "auth", "token"],
-                capture_output=True,
-                text=True,
-                timeout=5,
-            )
-        except (FileNotFoundError, subprocess.TimeoutExpired) as exc:
-            logger.debug("gh CLI token lookup failed (%s): %s", gh_path, exc)
-            continue
-        if result.returncode == 0 and result.stdout.strip():
-            return result.stdout.strip()
-    return None
-
 
 _PLACEHOLDER_SECRET_VALUES = {
     "*",