Prepare Mac-first v0.1 acceptance artifact

[DGPisces]

Summary

Prepare the Mac-first v0.1 acceptance candidate:

• retire GPU speech from the public default path
• add Provider API + macOS native speech helper
• replace the web console with Vite static packaging
• add packaged runtime, installer CLI, setup/doctor/start/update/uninstall
• add productized CI/release gates and public-tree audit
• rewrite public docs as a first Mac-first release

Test plan

• .venv/bin/python -m pytest
• cd frontend && npm run lint && npm run build && npm test
• bash -n install/install.sh install/uninstall.sh install/verify-release.sh scripts/build-macos-release.sh
• scripts/build-macos-release.sh --signing-mode skip --skip-frontend-build --skip-swift-build
• Release three-file local smoke using only install.sh, SHA256SUMS, and VocalizeAI-0.1.0-macos-arm64.zip
• Public candidate audit passed: 291 files checked

Review gate

Draft PR for CI and maintainer review. Do not merge until DGPisces approves and artifact human acceptance is complete.