v0.3.4

Added

• ref-audit --since <git-ref> (and doctor --since, forwarded): report only findings for notes changed since a git ref, narrowing the --check gate to the diff for pre-commit / CI. The scan stays graph-global; only the surfaced findings and the gate are scoped. A bad ref or non-git tree exits 2 rather than silently scanning the wrong scope. (Roadmap R15.)
• doctor run-receipt: every run emits a receipt (tool / version / root / files_scanned / engines_run / duration_ms) in --json and as the human report's header line, so a wrong-root or 0-file run fails loudly instead of passing as a silent green. (Roadmap R18.)