Add steady glow effect beneath hydrogen bomb

Render a soft radial glow underneath the hydrogen bomb sprite in
UnitPass. H-bomb instances draw an enlarged quad (hBombGlowScale) so
there's room for the halo; a cell-space UV remap keeps the sprite at its
normal size while the margin becomes glow area. The glow is a steady
(non-pulsing) radial falloff in a warm amber, alpha-blended underneath
the sprite and suppressed in alt/affiliation view.

Detection uses a HYDROGEN_BOMB_COL shader define derived from
UNIT_ORDER, so it tracks the atlas layout rather than hard-coding the
column. All other units are unaffected (scale 1, same fillrate); this
stays a single program / two instanced draw calls.

Glow color, scale, strength, and falloff are exposed in
render-settings.json for live tuning via the debug GUI.

src/client/render/gl/render-settings.json

@@ -179,7 +179,13 @@
     "flickerSpeed": 0.3,
     "angryR": 0.784,
     "angryG": 0,
-    "angryB": 0
+    "angryB": 0,
+    "hBombGlowScale": 2.2,
+    "hBombGlowR": 1.0,
+    "hBombGlowG": 0.72,
+    "hBombGlowB": 0.15,
+    "hBombGlowStrength": 0.5,
+    "hBombGlowInner": 0.45
   },
   "name": {
     "lerpSpeed": 10,