ci(build): add missing zip extension for static builds

[RVxLab]

This PR adds the missing zip PHP extension to the build pipeline.

When using the static build of clonio, dumping will successfully finish and then fail when trying to zip it all up. This doesn't happen with the PHAR version if the local PHP installation has ext-zip available.

Static build:

Failed to finalise dump archive: ZIP support unavailable — the PHP zip extension is not loaded.

PHAR build:

[2026-07-12T10:29:18.037692+00:00] INFO: dump_archived {"file":"my_database_20260712_102708.zip","bytes":1649395}
[2026-07-12T10:29:18.037745+00:00] INFO: run_finished {"success":true,"rows":25524}
[2026-07-12T10:29:18.037782+00:00] INFO: key_mapping_cleanup_completed
  Generating audit log .......................................................  ✓
  Delivering via local, stdout, stderr .......................................  ✓

  Tables: 30/30  Rows: 25524  Duration: 2m 9s

  Dump: my_database_20260712_102708.zip  (1.6 MB)