chore(theme): astro 锁定 ~5.18.0（终审 Minor）+ docs: Plan 4 收官

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

.deps_siteforge_v812/fastapi/security/utils.py

@@ -0,0 +1,10 @@
+from typing import Optional
+
+
+def get_authorization_scheme_param(
+    authorization_header_value: Optional[str],
+) -> tuple[str, str]:
+    if not authorization_header_value:
+        return "", ""
+    scheme, _, param = authorization_header_value.partition(" ")
+    return scheme, param.strip()