Restores pinned dependency versions for Rust

[dima-zakharov]

Pin libraries versions.

🔗 Related Issue

Pin rust libraries and maturin version as discussed in Slack

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📝 Summary

Restores pinned dependency versions for Rust tooling and adds stub files for the Rust plugin infrastructure.

Changes

 - Pin maturin version in pyproject.toml to ensure reproducible builds
 - Restore Cargo.lock files for plugins_rust/ and tools_rust/mcp_runtime/ directories (4,275 lines)
 - Add Python stub file (__init__.pyi) for url_reputation_rust module to improve type hints
 - Cleanup: Remove redundant .gitignore entries that were excluding lock files

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🏷️ Type of Change

• Bug fix
• Feature / Enhancement
• Documentation
• Refactor
• Chore (deps, CI, tooling)
• Other (describe below)

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🧪 Verification

Check	Command	Status
Build	make rust-build	Ok
Unit tests	make test	Ok
Coverage ≥ 81%	make coverage	Ok

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✅ Checklist

• Code formatted (make black isort pre-commit)
• Tests added/updated for changes
• Documentation updated (if applicable)
• No secrets or credentials committed

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📓 Notes (optional)

Chore task no functionality changes.