pakka v0.14.0

Measured output reduction: bench A/B runs persist per-repo measured reduction ratios; status line and RECEIPTS use them over the calibrated constant, with provenance disclosed (measured, n=K vs default calibration). Closes the per-session measurement promise from the enterprise-feedback cycle. Also fixes a data-loss bug where compress state entries with a failed validator run could clobber user edits with content from a stale snapshot. README now leads with gates/audit and gives explicit guidance for heavily cached environments. Assets are CI-built with SLSA provenance attestation, SHA256SUMS, and CycloneDX SBOM.