v0.12.0-rc3

This release candidate is cut from the head of develop. The notes below are written relative to v0.12.0-rc2; the changes that make up v0.12.0 itself are described in the v0.12.0-rc1 notes.

🚀 What's New

• exit_certificate: pending claims step and claimer support for unclaimed pre-certificate bridges (#1929): new standalone step --step pending_claims (not part of all) that lists the L2→L1 asset bridges emitted before the exit certificate that are still unclaimed on L1, and writes step-pending-l2-bridges.json. The exit_certificate_claimer gains an optional pendingBridgesPath (auto-detected in the exit_certificate output dir); GET /bridges and GET /claim-params then also serve those bridges, with proofs verified against the certificate's new_local_exit_root. No breaking changes.

Full Changelog: v0.12.0-rc2...v0.12.0-rc3