feat: persist required assets in transaction meta

[matthewwalsh0]

Explanation

Adds support for persisting requiredAssets on transaction metadata.

Use if available when generating required tokens.

References

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've communicated my changes to consumers by updating changelogs for packages I've changed
• I've introduced breaking changes in this PR and have prepared draft pull requests for clients and consumer packages to resolve them

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Note

Medium Risk
Adds a new persisted requiredAssets field to transaction/batch metadata and changes required-token computation to prefer this data when present, which can affect downstream transaction-pay behavior. Changes are optional/guarded but touch shared types and request plumbing used by multiple consumers.

Overview
Adds support for persisting requiredAssets on transactions and batches. addTransaction now accepts requiredAssets and stores it on TransactionMeta, and the batch (EIP-7702) flow forwards requiredAssets from the batch request into the created transaction.

Updates transaction-pay required-token generation to prefer explicit assets. parseRequiredTokens now builds required tokens from transactionMeta.requiredAssets when provided, falling back to parsing token transfers/gas fees only when absent/empty; tests and changelogs were updated accordingly.

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