Closes N2. The native WebDAV PUT handler now consults the lock
store before accepting a write: if the target path is exclusively
locked, the request must carry the lock token in its If: header
or the server returns 423 Locked. Without a matching token, the
body is never consumed — a rejected PUT no longer wastes the
upload bandwidth or hits the CDC ingester.
Two helpers are introduced so the same enforcement plugs into
the other mutator methods (delete/move/copy/proppatch) when their
fixes land:
extract_if_header_tokens — angle-bracket-scoop view of If:
(sufficient for one-target writes;
full §10.4 tagged-list grammar would
only matter for multi-resource Ifs)
enforce_native_lock — Some(423) when locked + no/wrong
token, None otherwise
Test N2 flipped from pinned 204 to assert 423. Added N2b: same
PUT with the captured Lock-Token in If:(<...>) returns 204, so a
regression that hard-rejected every PUT would still fail loudly.
Edouard Vanbelle
9f2ebd0758