* feat(aiproxy): support streaming responses for visual messages
* refactor(aiproxy): share API log helpers and support input/output token usage
Extract common chatlog record lifecycle across proxy handlers, and fall back
to Responses/Anthropic usage field aliases when filling token counts.
Promote visual_provider_id/visual_model_key to dedicated ai_model columns,
force non-stream upstream orchestration for visual paths, and synthesize SSE
chunks for streaming Responses requests that include images.
* refactor(aiproxy): rename chat log config to API log with S3 fields
* feat(aiproxy): add visual extension for Responses image tools
Wire visual model catalog, orchestration, and OpenAI Responses compat so chat/Codex can invoke image generation and editing tools.
