- IntersceneMatchParameters: add curt_synth_bg_avg (synth quick-run: average N=2^LEV real
  frames per output frame and force a single level — restores the fast synthetic+background path).
- CuasDetectRT: that fast synth path (decimate-average to a short sequence + single level),
  honoring "Time ROI to" for the averaged-sequence length.
- CuasDnnInfer: MF-S head reads channel 0 as the raw matched-filter path-sum (clamp>=0, no sigmoid).

Validated: weighted model tracks the real UAS sub-pixel at LEV2/3; linear conditioning
(LReLU off) is dropout-free and matches the no-LReLU training. Checkpoint before Layer 2.
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>