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

tests/unit/test_models.py

@@ -1,7 +1,6 @@
 from datetime import datetime, timedelta
 
-from mail_intake.models import MailIntakeMessage
-from mail_intake.models import MailIntakeThread
+from mail_intake.models import MailIntakeMessage, MailIntakeThread
 
 
 def test_message_is_immutable():
@@ -19,7 +18,7 @@ def test_message_is_immutable():
 
     try:
         msg.subject = "Changed"
-        assert False, "Message should be immutable"
+        raise AssertionError("Message should be immutable")
     except Exception:
         assert True