Add estimation hooks

[gndelia]

Description

This PR adds 2 extra hooks

• 892b508 Adds useEstimateFees, which is based on the implementation from the portal. There are a few minor differences though: That hook used to default to 0n when values were still loading or on error. Now, unless there's an exact estimation, undefined is returned. I think that's the best behaviour, and loading and error states should be handled. The default overEstimation is now 1.5 (instead of 1) as all usages in the portal were passing 1.5. And now the fallbackPriorityFee is a parameter for the consumer, instead of being hardcoded per chain (we only used it for hemiSepolia in the portal). Tests were added!
• 1dc0a50 Adds the hook to estimate approve operation for erc20 tokens.
• 99edfaa Bumps the version

Screenshots

Checklist

• Manual testing passed.
• Automated tests added, or N/A.
• Documentation updated, or N/A.
• Environment variables set in CI, or N/A.

[Copilot]

Pull request overview

Adds new fee-estimation utilities and hooks and wires up Vitest so consumers can estimate total EIP-1559 fees and ERC-20 approve costs with test coverage.

Changes:

• Added estimateTotalFee utility with a comprehensive Vitest suite.
• Added useEstimateFees and useEstimateApproveErc20Fees hooks for fee estimation flows.
• Introduced Vitest config/scripts and bumped package version.

Reviewed changes

Copilot reviewed 7 out of 9 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
vitest.config.ts	Adds Vitest configuration (clear mocks) to support the new test suite.
src/utils/fees.ts	Introduces estimateTotalFee utility used by the new hooks to compute total EIP-1559 fees.
src/utils/fees.test.ts	Adds unit tests validating fee estimation behavior and edge cases.
src/useEstimateFees.ts	Adds a hook that composes wagmi fee data with estimateTotalFee.
src/useEstimateApproveTokenFees.ts	Adds a hook to estimate ERC-20 approve gas and total fees.
package.json	Adds Vitest scripts/deps and bumps version for release.
README.md	Documents the two new hooks in the public API table.

Files not reviewed (1)

• pnpm-lock.yaml: Language not supported

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[ArturDolzan]

LGTM.