publish.yml default-branch title inference

Trap: resolving an ambiguous Publish title against the default-branch checkout looks authoritative because it contains Craft config, but release-branch workspace definitions may differ. Fix: new requests must carry dedicated versioned metadata binding the exact materialized release branch and SHA; Publish checks out that ref and requires CI success for that exact head before interpreting a trailing segment. Requests lacking the marker retain legacy path, checkout, and state semantics byte-for-byte.