docs(gallery): rebuild temp-override-join contact sheet against the current calibration set

#224 reported this hero's stage as brighter and cooler than the calibration
set (luma 0.3611 vs 0.15-0.30). Since then the example was redesigned twice
(#232, then #281 as a hurricane lantern) and calibration member armature-bend
was redesigned too, but the committed sheet still showed the old tiles.

Rebuilt with scripts/contact_sheet.py (committed heroes, no re-render):

  tile                     luma   stage  warmth   sat
  temp-override-join     0.2364 0.2164 +0.4660 0.1930
  armature-bend (cal)    0.2428 0.1919 -0.1440 0.2367
  damped-track-aim (cal) 0.2372 0.2180 +0.1052 0.1777
  bmesh-gear (cal)       0.2369 0.2517 +0.0921 0.1525

The candidate sits inside the calibration band on luma and stage. Warmth is
high from the lit globe, by design. A fresh render from code
(.scratch/blender-5.2.1-windows-x64, 5.2.1 LTS) measures luma 0.2363 /
stage 0.2163, so the committed hero matches its script. At full size it
shows the dark studio and a warm wall pool upper right. A relight sweep
(key 480->340 W, fill 90->60 W, wedge re-aimed) moved luma only to
0.223-0.228 with no visible gain, so the lighting is unchanged.

Closes #224

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: TMHSDigital