POC: Send native images through Claude sessions

[smsunarto]

Summary

• send supported local PNG, JPEG, GIF, and WebP attachments as native Claude image content
• send HTTP(S) image attachments as native URL image content
• validate local image data and fall back to Read-tool markers for invalid, unsupported, oversized, or over-budget inputs
• retain one base64 image budget across grouped messages, turns, and SDK stream recovery
• package Sharp for the host daemon, bb-app, and production bridge bundles

POC status

This is a work-in-progress proof of concept for review. Known follow-up items:

• requests with more than 20 native images need the stricter Anthropic dimension policy or a native-image count cap
• animated GIF/WebP validation currently decodes all pages, which can reject valid animations when Sharp reports stacked frame dimensions; Claude uses only the first frame
• no billed live-Claude smoke test has run

Validation

• pnpm exec turbo run test typecheck --filter=@bb/agent-runtime --force — 975 tests passed
• pnpm exec turbo run build --filter=@bb/host-daemon --filter=bb-app --force
• git diff --check

AGENT GENERATED: by GPT-5.4