standardize packaging, tooling, docs, CI, and licensing

mail_intake/adapters/base.py

@@ -12,7 +12,8 @@ types or semantics should leak beyond implementations of this interface.
 """
 
 from abc import ABC, abstractmethod
-from typing import Iterator, Dict, Any
+from collections.abc import Iterator
+from typing import Any
 
 
 class MailIntakeAdapter(ABC):
@@ -32,7 +33,7 @@ class MailIntakeAdapter(ABC):
     """
 
     @abstractmethod
-    def iter_message_refs(self, query: str) -> Iterator[Dict[str, str]]:
+    def iter_message_refs(self, query: str) -> Iterator[dict[str, str]]:
         """
         Iterate over lightweight message references matching a query.
 
@@ -63,7 +64,7 @@ class MailIntakeAdapter(ABC):
         raise NotImplementedError
 
     @abstractmethod
-    def fetch_message(self, message_id: str) -> Dict[str, Any]:
+    def fetch_message(self, message_id: str) -> dict[str, Any]:
         """
         Fetch a full raw message by message identifier.
 
@@ -78,7 +79,7 @@ class MailIntakeAdapter(ABC):
         raise NotImplementedError
 
     @abstractmethod
-    def fetch_thread(self, thread_id: str) -> Dict[str, Any]:
+    def fetch_thread(self, thread_id: str) -> dict[str, Any]:
         """
         Fetch a full raw thread by thread identifier.