feat: validateStakeCred

[slowbackspace]

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[Copilot]

Pull Request Overview

This PR adds a new validateStakeCred function that validates and extracts stake credentials from various Cardano address formats. The function supports multiple input formats including stake addresses, stake keys, stake key hashes, and script addresses, returning normalized stake credential information.

Key changes:

• Implements validateStakeCred function with support for multiple bech32 address formats
• Adds comprehensive test fixtures covering different stake credential types and networks
• Updates constant naming from Prefixes to PREFIXES for consistency

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
src/validation.ts	Implements the main validateStakeCred function and helper functions, updates prefix constants
test/fixtures/validation.ts	Adds comprehensive test fixtures for various stake credential formats
test/tests/validation.test.ts	Adds test cases for the new validateStakeCred function
CHANGELOG.md	Documents the new feature addition

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