feat: redesign site as a modern developer portfolio

- New home page: hero, stats, about, focus areas, stack, projects, contact
- Light/dark theme with system default and persisted toggle
- Content centralised in data/profile.js
- Restyle /rates to match; remove it from nav and projects
- Afriex: log a clear error now that its API requires a device id

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

pages/api/v1/rates.js

@@ -240,7 +240,11 @@ export default async (req, res) => {
             .catch((error) => reject(error));
     })
         .then((result) => {
-            const ngnRate = result.rates.EUR.NGN;
+            // Afriex now rejects unauthenticated requests with {"message":"Device id missing"}
+            const ngnRate = result?.rates?.EUR?.NGN;
+            if (!ngnRate) {
+                throw new Error(`Unexpected response: ${result?.message || JSON.stringify(result).slice(0, 200)}`);
+            }
             return {
                 rate: parseFloat(ngnRate).toFixed(2),
                 provider: "Afriex",
@@ -250,7 +254,7 @@ export default async (req, res) => {
             };
         })
         .catch((error) => {
-            console.error("Error calling Afriex:", error);
+            console.error("Error calling Afriex:", error.message);
             return createDefaultErrorResponse("Afriex", "https://www.afriex.com/");
         });