fix(logging): use print(flush=True) for TIMING lines so they appear in HF logs

revert(ocr): remove invalid det_model parameter

perf(ocr): switch to mobile detection model for faster CPU inference

revert(ocr): restore dual-pass and 4096px, keep timing logs

chore(ocr): add per-step timing logs to identify bottleneck

perf(ocr): halve inference time on free CPU tier

feat: initial OCR server deploy