Add AgglayerBridge benchmark model

[fricoben]

Adds a Phase 2 benchmark model for Polygon AgglayerBridge Merkle/nullifier claim integrity.

Includes:

• AgglayerBridge contract model and specs for successful claim validity/nullifier consumption
• Generated Phase 3 proof task placeholders
• Case/family metadata for the Polygon AgglayerBridge target
• Benchmark Lake target for the case modules

Validation:

• lake build Benchmark

Notes:

• Generated task files intentionally keep unresolved proof placeholders for Phase 3 and are not included in the Benchmark build target.
• The contract macro emits duplicate namespace warnings because the outer namespace and Solidity contract name both include AgglayerBridge.

[fricoben]

Closing this PR because the benchmark case belongs in lfglabs-dev/verity-benchmark, not lfglabs-dev/verity. I will reopen it against the benchmark repository.

[github-actions]

\n### CI Failure Hints\n\nFailed jobs: `compiler-audits`\n\nCopy-paste local triage:\n```bash\nmake check\nlake build\nFOUNDRY_PROFILE=difftest forge test -vv\n```