feat: add sendTransactionSync and writeContractSync to AbstractClient and SessionClient

[coffeexcoin]

Add sync transaction submission variants that use EIP-7966 eth_sendRawTransactionSync to wait for mining and return full transaction receipts instead of just hashes.

• Add sendTransactionSync and writeContractSync to AbstractClient and SessionClient, enabling EIP-7966 (eth_sendRawTransactionSync) support that waits for mining and returns a full transaction receipt instead of just a hash.
• Extend sendTransactionInternal with a generic TReturnType parameter and optional sendSerializedTransaction callback, keeping it fully backward compatible with all existing callers.
• Export sendTransactionSync, writeContractSync, sendTransactionForSessionSync, and writeContractForSessionSync from @abstract-foundation/agw-client/actions for direct usage.

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PR-Codex overview

This PR introduces synchronous transaction handling methods in the AbstractClient and SessionClient to support EIP-7966. It enhances the transaction capabilities by adding sendTransactionSync and writeContractSync, improving usability for synchronous operations.

Detailed summary

• Added sendTransactionSync and writeContractSync methods to AbstractClient and SessionClient.
• Exported new synchronous transaction methods in actions.ts.
• Updated sendTransactionInternal to accept a custom callback for serialized transactions.
• Created tests for new synchronous methods in writeContractSync.test.ts and sendTransactionSync.test.ts.
• Enhanced error handling in the synchronous transaction flow.
• Integrated sendTransactionForSessionSync for session-based transactions.

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[changeset-bot]

🦋 Changeset detected

Latest commit: 9465d6b

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 4 packages

Name	Type
@abstract-foundation/agw-client	Minor
@abstract-foundation/agw-react	Patch
@abstract-foundation/agw-web	Patch
@abstract-foundation/web3-react-agw	Patch

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PR Summary

Medium Risk
Touches core transaction submission by generalizing sendTransactionInternal and adding new synchronous send/write paths, which could impact signing/sending behavior if callback wiring is incorrect. Existing async behavior is intended to remain unchanged when the new callback is not provided.

Overview
Adds EIP-7966 synchronous transaction submission to @abstract-foundation/agw-client via new sendTransactionSync/writeContractSync actions (and session equivalents) that use eth_sendRawTransactionSync to return full receipts.

Updates sendTransactionInternal to accept an optional sendSerializedTransaction callback and generic return type, allowing callers to swap eth_sendRawTransaction for sync submission without changing the signing/prep pipeline.

Exposes these new methods on AbstractClient and SessionClient, exports them from actions, adds a changeset for a minor bump, and includes new unit tests covering sync flows (including Privy cross-app paymaster handling) and the new internal callback behavior.

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