standardize packaging, tooling, docs, CI, and licensing

mail_intake/parsers/headers.py

@@ -10,10 +10,8 @@ The functions here are intentionally simple and tolerant of malformed
 or incomplete header data.
 """
 
-from typing import Dict, List, Tuple, Optional
 
-
-def parse_headers(raw_headers: List[Dict[str, str]]) -> Dict[str, str]:
+def parse_headers(raw_headers: list[dict[str, str]]) -> dict[str, str]:
     """
     Convert a list of Gmail-style headers into a normalized dict.
 
@@ -50,7 +48,7 @@ def parse_headers(raw_headers: List[Dict[str, str]]) -> Dict[str, str]:
             }
         ```
     """
-    headers: Dict[str, str] = {}
+    headers: dict[str, str] = {}
 
     for header in raw_headers or []:
         name = header.get("name")
@@ -64,7 +62,7 @@ def parse_headers(raw_headers: List[Dict[str, str]]) -> Dict[str, str]:
     return headers
 
 
-def extract_sender(headers: Dict[str, str]) -> Tuple[str, Optional[str]]:
+def extract_sender(headers: dict[str, str]) -> tuple[str, str | None]:
     """
     Extract sender email and optional display name from headers.