feat: full-stack frontend with gateway API integration

- Dashboard with real-time service health, screening results, stream stats
- Stock list page with search, market filter, pagination via KIS API
- Stock detail page with prices, valuation, AI analysis, catalysts
- Screening page with trigger + results display
- Pipeline monitoring with service status and stream info
- Typed API client (lib/api.ts) for all gateway endpoints
- Reusable components (Sidebar, StatCard)
- Dockerfile with build-time NEXT_PUBLIC_API_URL injection
- Docker-compatible .dockerignore

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

src/app/globals.css

@@ -1,26 +1,33 @@
 @import "tailwindcss";
 
 :root {
-  --background: #ffffff;
-  --foreground: #171717;
+  --background: #0f172a;
+  --foreground: #e2e8f0;
+  --card: #1e293b;
+  --card-border: #334155;
+  --accent: #3b82f6;
+  --accent-green: #22c55e;
+  --accent-red: #ef4444;
+  --accent-yellow: #eab308;
+  --muted: #94a3b8;
 }
 
 @theme inline {
   --color-background: var(--background);
   --color-foreground: var(--foreground);
+  --color-card: var(--card);
+  --color-card-border: var(--card-border);
+  --color-accent: var(--accent);
+  --color-accent-green: var(--accent-green);
+  --color-accent-red: var(--accent-red);
+  --color-accent-yellow: var(--accent-yellow);
+  --color-muted: var(--muted);
   --font-sans: var(--font-geist-sans);
   --font-mono: var(--font-geist-mono);
 }
 
-@media (prefers-color-scheme: dark) {
-  :root {
-    --background: #0a0a0a;
-    --foreground: #ededed;
-  }
-}
-
 body {
   background: var(--background);
   color: var(--foreground);
-  font-family: Arial, Helvetica, sans-serif;
+  font-family: var(--font-sans), Arial, Helvetica, sans-serif;
 }