proxy: emit RunPod job status (siq_status) for live client feedback

fix: merge reasoning-effort into system msg (2nd system msg empties the worker)

fix: GGUF worker takes openai request directly as input (not openai_input envelope)

proxy: detect client disconnect via res close, not req close

proxy: async /run + poll path (works with the proven SIQ serverless worker)

siq-proxy: streaming OpenAI bridge to RunPod serverless SIQ-1