fix(release): update-apt-repo artifact download + dynamic GPG fingerprint (closes #96)

[levleontiev]

Fixes #96

Changes

release.yml — update-apt-repo job

1. Download .deb artifact: replaced actions/upload-artifact with actions/download-artifact@d3f86a1 (same SHA already used in smoke-test-deb and github-release).

2. Update apt repository: removed hardcoded fingerprint 45160BC066817A6E710F7BA0208922A1DA3B0CEC. The fingerprint is now derived dynamically after import:

   FINGERPRINT=$(gpg --with-colons --list-secret-keys 2>/dev/null | grep '^fpr' | head -1 | cut -d: -f10)
   ./edge-repo/bin/ci/update_apt_repo.sh "$DEB_FILE" "./apt-repo" "$FINGERPRINT"

   This means rotating GPG_PRIVATE_KEY secret requires no code change.

GPG key

A fresh RSA-4096 key (22DF05A7ACFD667DB9EE51A018BC4FF01C464181, Fairvisor Release <release@fairvisor.com>) has been generated and set as the GPG_PRIVATE_KEY secret in fairvisor/edge.

After merge → tag v0.2.5.