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/models/message.pyi

@@ -1,14 +1,24 @@
 from datetime import datetime
-from typing import Optional, Dict
 
 class MailIntakeMessage:
     message_id: str
     thread_id: str
     timestamp: datetime
     from_email: str
-    from_name: Optional[str]
+    from_name: str | None
     subject: str
     body_text: str
     snippet: str
-    raw_headers: Dict[str, str]
-    def __init__(self, message_id: str, thread_id: str, timestamp: datetime, from_email: str, from_name: Optional[str], subject: str, body_text: str, snippet: str, raw_headers: Dict[str, str]) -> None: ...
+    raw_headers: dict[str, str]
+    def __init__(
+        self,
+        message_id: str,
+        thread_id: str,
+        timestamp: datetime,
+        from_email: str,
+        from_name: str | None,
+        subject: str,
+        body_text: str,
+        snippet: str,
+        raw_headers: dict[str, str],
+    ) -> None: ...