fix: remove defaultBaseUrl fallback in TTS availability check

[tongshu2023]

Summary

Fixes #574 — TTS provider availability check produces false positives for local keyless providers.

Problem

The isKeylessLocalProvider condition in lib/audio/voice-resolver.ts included config.defaultBaseUrl as a fallback. This caused local keyless TTS providers (VoxCPM, Lemonade) to be marked as "available" even when the user had not deployed the corresponding server. Agents were then assigned to unreachable providers, resulting in silent TTS failures (connection refused) for some agents while others worked fine.

Root Cause

lib/audio/voice-resolver.ts lines 133-139 — the isKeylessLocalProvider check unconditionally accepted config.defaultBaseUrl as a valid URL, ignoring whether the user had actually deployed and configured the server.

Changes

• 1 file changed: lib/audio/voice-resolver.ts
• Removed config.defaultBaseUrl from the isKeylessLocalProvider availability check
• Local keyless providers are now only available when the user explicitly sets serverBaseUrl or baseUrl in their configuration

Test Plan

1. Deploy only Lemonade TTS server (do not deploy VoxCPM)
2. Do not configure VoxCPM base URL in settings
3. Generate a classroom
4. ✅ All agent voices should use providers with actual configured URLs (no VoxCPM)
5. ✅ Previously broken agents should no longer be assigned to unreachable providers

[YizukiAme]

Hello @tongshu2023! The fix itself is clean👍, but Prettier is failing:

pnpm exec prettier --check lib/audio/voice-resolver.ts
# Code style issues found in the above file.

Could you run pnpm exec prettier --write lib/audio/voice-resolver.ts and push the formatting fix? Should be a one-liner change.

[wyuc]

Thanks @tongshu2023, fix matches the #574 proposal exactly. Before merge:

• CI red on prettier. Run pnpm exec prettier --write lib/audio/voice-resolver.ts and re-push.
• Add a vitest: keyless provider with only defaultBaseUrl (no user-set serverBaseUrl/baseUrl) should NOT appear in the returned list.
• Add Related to #587 in the description. Its logs show lemonade-tts: fetch failed, consistent with this fix's symptom, but we can't tell from the report whether the user configured Lemonade explicitly. Worth asking the reporter to verify after merge.

Non-blocking: isLocalVoxCPM (lines 140–142 / 151) becomes redundant after this fix. Happy to take it as follow-up.