Add Nod under Audio

[dbarabashh]

0. I have read the Contribution Guidelines
1. I confirm that I have read and understood the sections about "AI"-adjacent software
2. Project URL: https://hellonod.app/
3. Why should this project be added: Nod is a native macOS (Swift) app whose core purpose is to record, transcribe and summarize meetings, calls and voice notes locally across 22+ tools (Zoom, Meet, Teams, etc.) — it is a meeting recorder/transcriber, not an LLM chat wrapper; transcription uses specialised speech models as part of that larger process. It is a paid app with a 14-day free trial for maintainers to validate. Privacy-first: audio is never stored, data is kept in the EU, no model training on user data. Not Electron.
4. End all descriptions with a full stop/period
5. Entry is ordered alphabetically (Audio section, between Murmur and Plug)
6. Appropriate icon(s) added if applicable (paid app, so no OSS/freeware icon)