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/ingestion/reader.pyi

@@ -1,4 +1,6 @@
-from typing import Iterator, Dict, Any
+from collections.abc import Iterator
+from typing import Any
+
 from mail_intake.adapters.base import MailIntakeAdapter
 from mail_intake.models.message import MailIntakeMessage
 from mail_intake.models.thread import MailIntakeThread
@@ -7,4 +9,4 @@ class MailIntakeReader:
     def __init__(self, adapter: MailIntakeAdapter) -> None: ...
     def iter_messages(self, query: str) -> Iterator[MailIntakeMessage]: ...
     def iter_threads(self, query: str) -> Iterator[MailIntakeThread]: ...
-    def _parse_message(self, raw_message: Dict[str, Any]) -> MailIntakeMessage: ...
+    def _parse_message(self, raw_message: dict[str, Any]) -> MailIntakeMessage: ...