Add rider/driver role selection after sign-up

- users.role column (+ migration in seed script)
- /(api)/user: GET role by clerkId, PATCH to set role
- Role selection screen; drivers get placeholder driver-home
- Root index routes by role; hardened location handling on home

app/(api)/user+api.ts

@@ -1,5 +1,26 @@
 import { neon } from "@neondatabase/serverless";
 
+export async function GET(req: Request) {
+  const sql = neon(process.env.DATABASE_URL!);
+  const clerkId = new URL(req.url).searchParams.get("clerkId");
+
+  if (!clerkId) {
+    return Response.json({ error: "Missing clerkId" }, { status: 400 });
+  }
+
+  try {
+    const response = await sql`
+      SELECT id, name, email, role FROM users WHERE clerk_id = ${clerkId}
+    `;
+
+    return Response.json({ data: response[0] ?? null });
+  } catch (error) {
+    console.log("[GET_USER]: ", error);
+
+    return Response.json({ error }, { status: 500 });
+  }
+}
+
 export async function POST(req: Request) {
   const sql = neon(process.env.DATABASE_URL!);
   const { name, email, clerkId } = await req.json();
@@ -36,3 +57,31 @@ export async function POST(req: Request) {
     return Response.json({ error }, { status: 500 });
   }
 }
+
+export async function PATCH(req: Request) {
+  const sql = neon(process.env.DATABASE_URL!);
+  const { clerkId, role } = await req.json();
+
+  if (!clerkId || !["rider", "driver"].includes(role)) {
+    return Response.json(
+      { error: "Missing clerkId or invalid role." },
+      { status: 400 },
+    );
+  }
+
+  try {
+    const response = await sql`
+      UPDATE users SET role = ${role} WHERE clerk_id = ${clerkId} RETURNING id, role
+    `;
+
+    if (response.length === 0) {
+      return Response.json({ error: "User not found." }, { status: 404 });
+    }
+
+    return Response.json({ data: response[0] });
+  } catch (error) {
+    console.log("[PATCH_USER]: ", error);
+
+    return Response.json({ error }, { status: 500 });
+  }
+}