feat(theme): finish neon-glass polish (#88)

Rewrite whole-swap rofi.rasi to rofi-native @colors (was invalid CSS
var()); cyan glass panel matching Boreal's hex-alpha pattern. btop
titles/selection in accent cyan; ui rounding/opacity tuned; preview.png
from theme-shot. Bar stays generated from JSON (no waybar.css).

Verified: V2 — contrast 24×7; theme-wholeswap; theme-shot neon-glass
desktop+menu viewed; boreal theme-shot regression green.

themes/neon-glass.json

@@ -28,14 +28,14 @@
     "size": 11
   },
   "ui": {
-    "gapsIn": 5,
-    "gapsOut": 12,
+    "gapsIn": 6,
+    "gapsOut": 14,
     "borderSize": 2,
-    "rounding": 10,
+    "rounding": 14,
     "iconSize": 36,
-    "activeOpacity": 1.0,
-    "inactiveOpacity": 0.95,
-    "terminalOpacity": 0.96,
+    "activeOpacity": 0.96,
+    "inactiveOpacity": 0.90,
+    "terminalOpacity": 0.94,
     "blur": true,
     "shadow": true
   },