Rebuild frontend with Tailwind CSS + fix Python 3.14 compatibility

- Upgrade SQLAlchemy 2.0.27→2.0.45, google-genai SDK for Python 3.14
- Replace google-generativeai with google-genai in narrative_service.py
- Fix HTTPException handling in main.py (was wrapping as 500)
- Rebuild all frontend components with Tailwind CSS v3:
  - Dashboard, NarrativeSection, StatsGrid, VibeRadar, HeatMap, TopRotation
  - Custom color palette (background-dark, card-dark, accent-neon, etc.)
  - Add glass-panel, holographic-badge CSS effects
- Docker improvements:
  - Combined backend container (API + worker in entrypoint.sh)
  - DATABASE_URL configurable via env var
  - CI workflow builds both backend and frontend images
- Update README with clearer docker-compose instructions

frontend/tailwind.config.js

@@ -0,0 +1,34 @@
+/** @type {import('tailwindcss').Config} */
+export default {
+  content: [
+    "./index.html",
+    "./src/**/*.{js,ts,jsx,tsx}",
+  ],
+  darkMode: "class",
+  safelist: [
+    'bg-primary/20', 'text-primary', 'border-primary/20',
+    'bg-accent-purple/20', 'text-accent-purple', 'border-accent-purple/20',
+    'bg-accent-neon/20', 'text-accent-neon', 'border-accent-neon/20',
+  ],
+  theme: {
+    extend: {
+      colors: {
+        "primary": "#256af4",
+        "background-light": "#f5f6f8",
+        "background-dark": "#101622",
+        "card-dark": "#182234",
+        "card-darker": "#111927",
+        "accent-neon": "#0bda5e",
+        "accent-purple": "#8b5cf6",
+      },
+      fontFamily: {
+        "display": ["Space Grotesk", "sans-serif"],
+        "mono": ["Space Grotesk", "monospace"],
+      },
+      backgroundImage: {
+        'gradient-radial': 'radial-gradient(var(--tw-gradient-stops))',
+      }
+    },
+  },
+  plugins: [],
+}