Replace custom FunnelChart with 21st.dev funnel-chart component

Drops in the exact 21st.dev FunnelChart component with motion/react,
curved bezier segments, layered rings, and spring hover animations.
Removes the previous custom SVG implementation.

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

package.json

@@ -28,6 +28,7 @@
     "iso-3166-2": "^1.0.0",
     "jspdf": "^4.0.0",
     "jspdf-autotable": "^5.0.7",
+    "motion": "^12.35.2",
     "next": "^16.1.1",
     "radix-ui": "^1.4.3",
     "react": "^19.2.3",