bce-engine v0.2.0 — evidence recovery

Immutable supplemental evidence for bce-engine@0.2.0. The canonical v0.2.0 release was published and frozen before its assets could upload (GitHub Actions run 33940706575, attempt 2). This release is anchored to the same source commit, 14716bf. The EvidenceRecord is the exact pre-publish record preserved in the run log; its Sigstore bundle was recovered from public Rekor entry 108e9186e8c5677a2a4ca6bb093fd4f840ee998feb75da9566762f5db8b73eebbf8a95abd5de72d3 and independently verified against the original release.yml@refs/tags/v0.2.0 GitHub Actions identity. This is evidence recovery, not a second package release.