feat: update pessimistic mode

[invocamanman]

Description

• Do not check "l1head" in optimistic mode (ECDSA).
• Add extra fields to the signature to accommodate future upgrades and enhance robustness.
• Update the claim indexes for claim Bridge exits

PR Checklist:

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added or updated tests that comprehensively prove my change is effective or that my feature works

[Ekleog-Polygon]

Overall LGTM! Though I'm not familiar with the aggchain proof domain just yet; I'll let @hadjiszs approve formally once his comments will be handled :)