[Pepps233]

Summary

Migrate Anthropic, Google GenAI, Mistral, and OpenAI to their latest stable SDKs.

Reasoning

Adopt current SDK APIs without introducing automatic Google continuation requests or breaking browser bundles. Keep authentication paths unchanged; Google does not use GitHub credentials.

Changes

• Pin Anthropic 1.3.0, Google GenAI 2.31.0, Mistral 3.2.0, and OpenAI 7.43.0; synchronize the standalone Anthropic example and all distribution locks.
• Disable automatic continuation in Gemini and Vertex; preserve length/error finishes even when output contains tool calls.
• Adopt Anthropic API 2026-10-21 sampling removal and context-window stop reason, and native OpenAI cache-option types.
• Use scoped Mistral Chat/HTTPClient imports to avoid eagerly loading Node-only voice components in browser bundles.
• Review Google's unchanged no-op preinstall and update version-specific allowlists; all installs skipped lifecycle scripts.
• Replace a hoisting-dependent Cloudflare SDK mock with an in-memory SSE fetch stub and document migration behavior.

Testing

• npm run check passed, including browser smoke.
• ./test.sh passed with credentials isolated.
• Modified provider regressions and Cloudflare offline tests passed directly.
• Distribution lock regression tests passed.
• Clean external-only distribution-lock install in a temporary directory passed.
• Standalone Anthropic example lock audit: zero vulnerabilities. Existing Zod findings remain in the repository dependency chain; no billable provider calls were made.