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/credentials/__init__.pyi

@@ -1,5 +1,5 @@
-from .store import CredentialStore
 from .pickle import PickleCredentialStore
 from .redis import RedisCredentialStore
+from .store import CredentialStore
 
 __all__ = ["CredentialStore", "PickleCredentialStore", "RedisCredentialStore"]