petrol-v8b — single-pass max-information

Single 22.7 MB ONNX (havengo's proven-best weights). v8b drops the TTA passes that timed out in v8 and keeps only the information-adding components that fit in single-pass latency:

• CLAHE on the L-channel (rescues low-contrast / dusk frames)
• Mean-color letterbox padding (vs grey 114) — fewer edge false positives
• WBF fusion within single pass (per-class)
• Class-aware confidence thresholds (pumps lower, canopy higher)
• Geometric sanity filter (drops 0px or full-image junk)

The honest local benchmark proved filtering moves (agreement gates) hurt scores. v8b only filters obvious geometric junk and uses information-adding preprocessing.

Repo size: 22.7 MB. Expected p95 latency: ~1.4–1.8 s (well under 10 s gate).