chore(release): 0.0.3

Squash-merge lib-standardisation: adopt repo standards across packaging,
tooling, docs, and CI.

- standardize pyproject.toml (canonical packaging, lint config, extras, GSDFC pydoclint)
- add py.typed marker, modernize type hints and Google-style docstrings
- nest generated docs under docs/lib and docs/mcp; add hand-written wiki
- adopt standard Type A PyPI CI pipeline (tag==version guard + quality gate)
- promote generated CHANGELOG.md; bump version to 0.0.3

mail_intake/adapters/base.pyi

@@ -1,10 +1,11 @@
 from abc import ABC, abstractmethod
-from typing import Iterator, Dict, Any
+from collections.abc import Iterator
+from typing import Any
 
 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]]: ...
     @abstractmethod
-    def fetch_message(self, message_id: str) -> Dict[str, Any]: ...
+    def fetch_message(self, message_id: str) -> dict[str, Any]: ...
     @abstractmethod
-    def fetch_thread(self, thread_id: str) -> Dict[str, Any]: ...
+    def fetch_thread(self, thread_id: str) -> dict[str, Any]: ...