fix(rime): remove Arcana model support

[naszzz]

Summary

• Remove Arcana from the Rime plugin runtime paths, public model types, examples, and tests.
• Change the no-argument Rime TTS model to Coda while keeping the existing Astra speaker.
• Keep Lyra for callers that explicitly select Coda without a speaker.
• Apply repetition_penalty, temperature, top_p, max_tokens, and other supported request controls to Coda.
• Add unit coverage for Coda defaults and request controls.

⚠️ Rime's public cloud cutoff is August 15, 2026 at 12:00 UTC. Set model to coda when you upgrade. Astra is available on Coda, so the no-argument path keeps its established speaker for voice continuity.

Migration notice: https://docs.rime.ai/docs/arcana-sunset

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[tinalenguyen]

could we throw a logger.warning when the user sets model="arcana" for the plugin?