Three coupled improvements from tonight's design discussion with Andrey:

1. ZERO-DC in CuasConditioning (Config default ON): LWIR microbolometers are
   ADDITIVE (fixed tau=8ms exposure, F#~1 for NETD, ~100 counts/K) - day/night
   and seasons SHIFT the level, never scale it; the MCLT has no clean DC/AC
   separation, so a large DC (current ~-3500 counts under ~300 counts AC)
   spreads over many TD points and costs float32 mantissa bits. Subtract ONE
   common constant from all 16 sensors (pure shift, never rescale). AUTO level
   = MEDIAN OF THE TOP (SKY) HALF, robust to the snowy-ground-vs-summer-
   calibration mismatch and to targets.

2. RT-DECOUPLED FAT ZERO (curt.fz_inter=10000, curt.fz_intra=2000 reserved):
   the lean code erroneously used the INTRA getGpuFatZero (2000) instead of
   the INTER value - Andrey's FZ sweep (200/1000/3000/10000: corrRMS
   .54/.39/.37/.31, roll bias +.80/+.62/+.50/+.39) independently rediscovered
   the oracle's INTER operating point (10000). RT now owns its FZ pair, no
   AUX switch; legacy gpu_fatz*/FOPEN configs untouched. Sweep recorded as
   characterization: FZ tolerant over a broad range; revisit only together
   with the argmax method redesign (sharp peaks starve the centroid).

3. BORROWED-CENTER APPROPRIATION (curt.dc_center, 0=auto): the restored
   CenterClt reflects its own footage vintage - offset it ONCE at the borrow
   boundary (firewall: never re-compensate downstream) to match the zero-sky
   scenes. Auto level = sky-half median of the borrowed center average,
   ADOPTED into curt.dc_center (persisted with the config - borrowable later
   like the photometric calibration). Mechanics: DC pattern = CLT of a
   uniform image via the existing back-propagation convert (setImageCenter +
   no_kernels + use_center_image, the CorrectionFPN recipe); failure-safe
   (any missing piece leaves the reference unchanged, with a warning).

Roadmap recorded: per-pixel offset (recalibrated per-sensor + FPN) and
per-pixel scale maps to the GPU; the average stored in TD AFTER LoG
(aberration+LoG combined kernels) for fpixels subtraction - possibly for
poses too; center-average window length trades reference stability vs
extremely-slow-target detectability.

Verified: mvn -DskipTests clean package OK.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>