Restyle dark theme with blue-tinted palette, card glow, and rounded surfaces

Shift the dark theme from neutral gray to a richer blue-tinted palette
inspired by CharBuilder-style TTRPG apps. Deeper navy background, steel-blue
card surfaces, and visible blue borders create more depth and visual layering.

- Update design tokens: background, card, border, input, muted colors
- Add card-glow utility (radial gradient + blue box-shadow) for card surfaces
- Add panel-glow utility (top-down gradient) for tall panels like stat blocks
- Apply glow and rounded-lg to all card surfaces, dropdowns, dialogs, toasts
- Give outline buttons a subtle fill instead of transparent background
- Active combatant row now uses full border with glow instead of left accent

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/web/src/components/ui/button.tsx

@@ -9,7 +9,7 @@ const buttonVariants = cva(
 			variant: {
 				default: "bg-primary text-primary-foreground hover:bg-primary/90",
 				outline:
-					"border border-border bg-transparent text-foreground hover:bg-hover-neutral-bg hover:text-hover-neutral",
+					"border border-border bg-background/50 text-foreground hover:bg-hover-neutral-bg hover:text-hover-neutral",
 				ghost:
 					"text-foreground hover:bg-hover-neutral-bg hover:text-hover-neutral",
 			},