Docs/audio-mixer-readme (AUD-7142)

[bryghtlabs-richard]

Description

Improve README.me by fixing links, translating a line, and tidying some code.

Testing

I rendered the markdown on my github branch.

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Checklist

Before submitting a Pull Request, please ensure the following:

• 🚨 This PR does not introduce breaking changes.
• All CI checks (GH Actions) pass.
• Documentation is updated as needed.
• Tests are updated or added as necessary.
• Code is well-commented, especially in complex areas.
• Git history is clean — commits are squashed to the minimum necessary.

[CLAassistant]

All committers have signed the CLA.