Krisp

Build me a noise-cleanup tool to replace Krisp for recordings, not live calls. Requirements: - Be honest in the README up front: real-time suppression as a virtual microphone needs an OS-level audio driver and millisecond latency. That is Krisp's actual product and it is out of scope here. This tool cleans audio files after the fact. - A CLI: `denoise in.wav` (mp3/m4a accepted, decoded via ffmpeg) writes in.clean.wav next to the original, original untouched. - Use RNNoise for the suppression pass (ffmpeg's arnndn filter with a downloaded model file is the easy route), then a loudnorm pass so voice levels come out consistent. - A watch mode with chokidar: drop files into ~/Denoise/in/ and cleaned versions appear in ~/Denoise/out/ with the same names. - Batch mode for whole folders, with a printed before/after noise estimate per file. - Node wrapping ffmpeg, or a plain bash script if that ships simpler. No server, no GUI. - Fully local and offline: no accounts, no telemetry, no API calls. - Out of scope: live call processing and a virtual audio device. For live calls the README should point me at the OS's built-in voice isolation instead. - README: ffmpeg and RNNoise model install, one-line usage examples.