fix: GSDFC docstring conformance, modernize legacy typing to match signatures; regenerate lib/MCP docs (pydoclint zero)

mail_intake/parsers/headers.py

@@ -16,11 +16,11 @@ def parse_headers(raw_headers: list[dict[str, str]]) -> dict[str, str]:
     Convert a list of Gmail-style headers into a normalized dict.
 
     Args:
-        raw_headers (List[Dict[str, str]]):
+        raw_headers (list[dict[str, str]]):
             List of header dictionaries, each containing `name` and `value` keys.
 
     Returns:
-        Dict[str, str]:
+        dict[str, str]:
             Dictionary mapping lowercase header names to stripped values.
 
     Notes:
@@ -67,11 +67,11 @@ def extract_sender(headers: dict[str, str]) -> tuple[str, str | None]:
     Extract sender email and optional display name from headers.
 
     Args:
-        headers (Dict[str, str]):
+        headers (dict[str, str]):
             Normalized header dictionary as returned by `parse_headers()`.
 
     Returns:
-        Tuple[str, Optional[str]]:
+        tuple[str, str | None]:
             A tuple `(email, name)` where `email` is the sender email address
             and `name` is the display name, or `None` if unavailable.