// Package multimodal groups the runtime's non-text input/output handling:
// image understanding (vision) and speech (voice).
//
// It follows DevDocs/design/06-多模态.md:
//
//   - The vision subpackage routes image messages through a layered strategy
//     (main model first, then a tool-shaped vision/OCR adapter) and registers
//     those adapters as sdk.Tool capabilities so the M2 tool loop can invoke
//     them without putting the image in the main-model context.
//   - The voice subpackage provides asynchronous STT/TTS through a degrading
//     provider chain (cloud → local → edge-tts/espeak → silent).
//
// Both subpackages keep real provider calls behind interfaces with an HTTP
// default implementation, so they are testable with a stdlib httptest server
// and leave the real cloud/local providers as adaptation points for later
// milestones.
package multimodal