cctp-rs 3.0.0

Rust SDK for CCTP
Documentation
# Pull Request

## Description
Brief description of what this PR does.

## Type of Change
- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
- [ ] Documentation update
- [ ] Performance improvement
- [ ] Code cleanup/refactoring

## Related Issues
Fixes #(issue number)

## Changes Made
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## Testing
- [ ] I have added tests that cover my changes
- [ ] All new and existing tests pass locally with my changes
- [ ] I have tested the examples and they work correctly

## Code Quality
- [ ] My code follows the style guidelines of this project
- [ ] I have performed a self-review of my own code
- [ ] I have commented my code, particularly in hard-to-understand areas
- [ ] My changes generate no new compiler warnings
- [ ] I have run `cargo clippy` and addressed any issues
- [ ] I have run `cargo fmt` to format my code

## Documentation
- [ ] I have updated the documentation accordingly
- [ ] I have updated the README if needed
- [ ] I have added docstrings to new public functions/methods
- [ ] My changes don't break existing documentation

## Security
- [ ] My changes don't introduce any security vulnerabilities
- [ ] I have considered the security implications of my changes
- [ ] I have not exposed any sensitive information (keys, tokens, etc.)

## CCTP Specific
- [ ] I have tested against the correct CCTP contract addresses
- [ ] I have verified domain IDs are correct for new chain support
- [ ] I have tested attestation flow if applicable
- [ ] My changes maintain compatibility with Circle's CCTP protocol

## Additional Notes
Any additional information or context about the PR.