Add tests for the MCP tools' degradation contracts, malformed WebDAV
multistatus bodies, dry-run poller sweeps including the circuit-open and
discover-failure paths, FS source scheme and symlink handling, docling-serve
zip parsing, and the remaining embedding and reranker helpers. Parametrize
_strip_etag.
Drop the misplaced pragma on the analyze handler, which sat on the return and
left the except uncovered. Add one on the FS symlink OSError guard, which
resolve(strict=False) absorbs for every real link.
