Add fallback logic to find potentialcommon ancestor using future milestones when no whitelisted milestone exists in the current chain. Such scenario usually happens in a devnet. This prevents nodes from getting stuck on wrong forks during milestone verification.

The issue occurs when nodes are on a fork and receive a new milestone:

• Existing logic only checks whitelisted milestones in current chain
• If current chain has no whitelisted milestones, rewind defaults to milestone start-1
• This can leave nodes on wrong fork instead of finding actual common ancestor

New logic adds findCommonAncestorWithFutureMilestones() which:

• Reads future milestone list from database (contains previously failed milestones)
• Searches from newest to oldest milestone to find matches with local chain
• Returns matching milestone block number to minimize rewind distance
• Falls back to calculated target block if no matches found

Changes

• Bugfix (non-breaking change that solves an issue)
• Hotfix (change that solves an urgent issue, and requires immediate attention)
• New feature (non-breaking change that adds functionality)
• Breaking change (change that is not backwards-compatible and/or changes current functionality)
• Changes only for a subset of nodes

Breaking changes

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Nodes audience

In case this PR includes changes that must be applied only to a subset of nodes, please specify how you handled it (e.g. by adding a flag with a default value...)

Checklist

• I have added at least 2 reviewer or the whole pos-v1 team
• I have added sufficient documentation in code
• I will be resolving comments - if any - by pushing each fix in a separate commit and linking the commit hash in the comment reply
• Created a task in Jira and informed the team for implementation in Erigon client (if applicable)
• Includes RPC methods changes, and the Notion documentation has been updated

Cross repository changes

• This PR requires changes to heimdall
  • In case link the PR here:
• This PR requires changes to matic-cli
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Testing

• I have added unit tests
• I have added tests to CI
• I have tested this code manually on local environment
• I have tested this code manually on remote devnet using express-cli
• I have tested this code manually on amoy
• I have created new e2e tests into express-cli

Manual tests

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Additional comments

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