docs: add Rust implementation to README

Author: Alex-Wengg

README.md

@@ -85,6 +85,13 @@ Contributing
 We welcome community contributions! Please refer to the [CONTRIBUTING.md](CONTRIBUTING.md) for guidelines.
 
 
+Alternative Implementations
+---------------------------
+
+### text-processing-rs
+
+[text-processing-rs](https://github.com/FluidInference/FluidAudio/tree/main/text-processing-rs) - Rust port supporting ITN and TN with 98.6% NeMo test compatibility (1200/1217 tests passing). Provides C FFI for Swift/Python integration and standalone CLI tools. Apache 2.0 licensed.
+
 
 Citation
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