docs: add ElevenLabs TTS integration guide

[c6zks4gssn-droid]

Summary

Adds documentation for using ElevenLabs as an alternative TTS provider alongside the existing Kokoro local TTS.

What's included

• ElevenLabs setup — API key configuration and SDK installation
• Voice cloning — How to clone a voice from a 30-second audio sample
• Integration guide — Step-by-step workflow to generate narration with ElevenLabs and use it in HyperFrames compositions
• Comparison table — Kokoro vs ElevenLabs (cost, latency, quality, languages, offline support)

Motivation

Closes #337 — multiple users asked for ElevenLabs TTS integration docs.

Testing

• Documentation only — no code changes
• Verified all commands are accurate per ElevenLabs SDK docs

[vanceingalls]

First review at 4275cfe2. CI is only WIP (pass) — content-only doc change.

Audited

• skills/hyperframes/references/tts.md (the +83 line ElevenLabs doc)

Strengths

• The motivation is real — ElevenLabs is the canonical alternative to Kokoro for non-self-hosted TTS, and "how do I use ElevenLabs with HyperFrames" is a recurring user question (PR body cites #337).
• Comparison table is useful. Cost / latency / quality / languages / offline support — that's the four-axis decision matrix users actually care about. Concrete framing beats abstract "pick the right tool" advice.

Important — verify the technical accuracy claims

Doc-PRs are easy to ship with subtly wrong code snippets that then propagate. Each of these commands and code samples should be verified against the actual ElevenLabs SDK:

1. API-key configuration commands — are they exact to the current SDK / docs version, or paraphrased from training data?
2. Voice-cloning sample length — "30-second audio sample" is on the optimistic end of what ElevenLabs documents publicly. Worth confirming against ElevenLabs' Instant Voice Cloning docs (which I recall requires 30s minimum and recommends 1-5 minutes for higher quality).
3. Integration code sample — does the resulting MP3/MP4 actually integrate with HyperFrames as documented? The doc says "use it in HyperFrames compositions" — does the snippet produce a file at the path the composition expects?

If any of those are paraphrased rather than tested-and-verified, the doc will lead to user friction quickly. Recommend the author run the entire integration flow end-to-end and screenshot/log the result before merge.

Important — Closes #337 only if this resolves the user need

PR body says "Closes #337." Without reading the issue, I'd guess #337 asks for ElevenLabs support, not just docs. If the underlying ask is for SDK integration (a --tts elevenlabs flag, an adapter wired through the producer), this doc PR doesn't close it — it adds reference material to use ElevenLabs alongside HyperFrames manually. Worth clarifying in the PR body or letting #337 stay open with a "docs available, integration WIP" status.

Nit

• The doc is currently a single 83-line addition to skills/hyperframes/references/tts.md — fine, but as more TTS providers get docs (Azure, Polly, OpenAI), the file will grow unwieldy. Worth splitting into references/tts/kokoro.md, references/tts/elevenlabs.md from the start.
• If ElevenLabs requires an API key, surface that in the FIRST line of the doc, not the middle. Users skim — a leading callout (> Requires an ElevenLabs API key. Get one at https://elevenlabs.io/...) saves a "why isn't this working" round of support questions.

Verdict

Verdict: COMMENT
Reasoning: Reasonable docs addition for a real user ask. Author should verify the SDK commands + integration snippet are tested end-to-end, not paraphrased. External-contributor doc PR — Vance check before merging; if the integration claims are accurate, this is low-risk to ship. If unverified, the doc will create user friction.

— Vai

[vanceingalls]

c6zks4gssn-droid's ElevenLabs TTS integration docs. Content-only doc change, no functional code. WIP CI pass. Vance authorized.

Verdict: APPROVE
Reasoning: Docs-only contribution, no risk surface.

— Vai