Batch claim across all of a user's vesting schedules

[joelpeace48-cell]

Epic: Advanced Contract Features

Summary

Add a helper to claim all currently-unlocked vested amounts in one transaction.

Background & Problem

Users with many schedules shouldn't pay N transactions to claim; a batched claim improves UX and fees.

Acceptance Criteria

• One call claims all unlocked amounts.
• Respects per-schedule limits.
• Gas-bounded for large N (paginated if needed).

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Filed as part of the mainnet-readiness & world-class roadmap. Scope is intentionally small enough for one focused PR; comment to claim.