Update automerge library to 1.0.0-beta.3 and Rust nightly to 2024-12-01

[Copilot]

This PR updates the Rust automerge library from version 0.6.1 to 1.0.0-beta.3, bringing the latest features and improvements to the automerge-swift package.

Changes Made

Library Updates

• automerge: 0.6.1 → 1.0.0-beta.3 (major version update)
• Rust toolchain: nightly-2024-05-23 → nightly-2024-12-01 (required for new dependencies)
• uniffi: Kept at 0.28.2 (0.29.4 has breaking changes that would require extensive additional work)

API Compatibility Fixes

The automerge 1.0.0-beta.3 update introduced several breaking changes that have been addressed:

1. Mark struct lifetime parameters removed: Updated mark.rs to handle the new Mark struct without lifetime parameters
2. MapRangeItem field access changes: Updated doc.rs to use item.id() method instead of direct field access
3. New ValueRef type system: Added conversions between the new ValueRef/ScalarValueRef types and the local wrapper types
4. Borrow checker fixes: Resolved ownership issues in iterator patterns

Code Quality

• Fixed clippy warnings including redundant .into_iter() calls
• Maintained consistent code formatting with rustfmt
• All existing functionality preserved with no breaking changes to the Swift API

Testing

• ✅ Rust code compiles and builds successfully in both debug and release modes
• ✅ All static analysis checks (rustfmt, clippy) pass
• ✅ Build scripts work correctly with the new Rust nightly version
• ✅ Existing Swift API remains unchanged - no breaking changes for consumers

Benefits

This update provides access to the latest automerge improvements and bug fixes while maintaining full backward compatibility. The changes are minimal and surgical, focusing only on the necessary compatibility updates to work with the new automerge API.

The updated Rust nightly version (2024-12-01) ensures compatibility with modern Rust ecosystem dependencies and provides access to the latest language features and optimizations.

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