The six `raise TypedError(...) from exc` sites (manifest.py x3, materialize.py,
connectors.py x2) turn leaked OSError / ValueError / sqlite3.Error / URLError
into typed IngestErrors while keeping the original under __cause__ — but no
test asserted the chain, so a stray bare `raise` could drop the cause
unnoticed. Add a conformance suite, one test per site, each asserting the
chained cause type. The module docstring documents the invariant. Companion
to test_error_codes.py, which pins the `.code` on the same sites.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HBbjgS5A55RVavoyjJC4FX
