Add HSV colour-space segmentation (lighting-robust colour location)

[JE-Chen]

find_color_region masks in RGB with a per-channel ± box — it can't match "the same colour at a different brightness" (status lights, highlights, theme tints). HSV separates hue from saturation/value, so a hue band + S/V floor catches every shade across lighting.

• dominant_hue_regions (AC_dominant_hue_regions): constrains only hue (± hue_tol) plus a sat_min/val_min floor, returning blob boxes at any brightness. Red's 0/180 hue wrap is handled automatically (two-range OR).
• segment_hsv (AC_segment_hsv): explicit lower_hsv..upper_hsv band → blob boxes. color_mask returns the raw uint8 mask.
• Reuses the shared cv2_utils.blobs.connected_boxes helper; injectable RGB haystack → headless-testable (synthetic bright + dark red prove the brightness-invariance RGB can't do). Base OpenCV only, lazy imports. Wired through all 5 layers + headless test + EN/Zh docs + WHATS_NEW. Qt-free.

[codacy-production]

Not up to standards ⛔

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

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