feat: Luminous Depth UI redesign

Complete visual overhaul of the Aryx application with the Luminous Depth
design language — blue-tinted dark surfaces, brand gradient accents,
glass-morphism effects, and refined typography.

Design Foundation:
- New color system with CSS custom properties for all surfaces, borders,
  text, accents, and status colors
- Typography: Outfit (display), DM Sans (body), JetBrains Mono (code)
- Animations: accent-flow, thinking-wave, ambient-glow
- Utility classes: glass-surface, glow-border, brand-gradient-bg/text
- Light theme with cool-tinted whites and blue-tinted shadows

Components Updated:
- UI primitives (TextInput, SelectInput, ToggleSwitch, FormField, etc.)
- AppShell with ambient glow background
- Sidebar with brand gradient selection and accent-flow running bars
- ChatPane with semantic phase tinting and gradient user avatars
- WelcomePane with nebula background and motion entrance animations
- All chat banners (Approval, UserInput, PlanReview, MCP Auth, etc.)
- ActivityPanel and RunTimeline with glass-surface cards
- Settings panels, modals, and editor shells
- TerminalPanel with harmonized ANSI palette
- PatternGraph nodes with glass-surface styling
- MarkdownComposer toolbar

Zero hardcoded zinc/indigo color classes remain in renderer components.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/renderer/components/ProviderIcons.tsx

@@ -51,9 +51,9 @@ const iconComponents: Record<ModelProvider, React.FC<{ className?: string }>> =
 };
 
 export const providerColors: Record<ModelProvider, string> = {
-  openai: 'text-emerald-400',
-  anthropic: 'text-orange-400',
-  google: 'text-blue-400',
+  openai: 'text-[var(--color-status-success)]',
+  anthropic: 'text-[var(--color-accent-purple)]',
+  google: 'text-[var(--color-status-info)]',
 };
 
 export function ProviderIcon({ provider, className }: ProviderIconProps) {