- openai_compat: extract reasoning_content from streaming SSE deltas,
benefiting providers like DeepSeek, Mimo, and Kimi that return
chain-of-thought content in streamed chunks
Media handling refactor (addresses review feedback):
- agent: centralize video/audio inline decisions in resolveMediaRefs
with provider capability gating via VideoCapable/AudioCapable interfaces
- agent: add mediaInlinePolicy + mediaInlinePolicyFromProvider() to probe
provider capabilities before encoding media as data URLs
- agent: add size guard via encodeMediaToDataURL (respects MaxMediaSize)
- providers: add VideoCapable and AudioCapable interfaces (same pattern as
ThinkingCapable/NativeSearchCapable)
- openai_compat: implement SupportsVideo/SupportsAudio for Mimo, Qwen,
OpenAI (host and providerName detection)
- httpapi: delegate SupportsVideo/SupportsAudio through HTTPProvider
- httpapi: GeminiProvider declares video + audio support
- common: add video_url serialization in SerializeMessages (now reachable
via the centralized pipeline); fix missing continue after audio branch
- Tests for capability detection, inline policy, oversized media skip,
and provider-unsupported media fallback to path tags
