feat(web): implement public profile page with Open Graph meta tags for /u/:username

apps/backend/src/app.ts

@@ -21,6 +21,7 @@ import { followRoutes } from './routes/follow.js';
 import { nfcRoutes } from './routes/nfc.js';
 import { profileRoutes } from './routes/profiles.js';
 import { publicRoutes } from './routes/public.js';
+import { publicCardRoutes } from './routes/publicCards.js';
 import { validateEnv } from './utils/validateEnv.js';
 
 const __dirname = path.dirname(fileURLToPath(import.meta.url));
@@ -103,6 +104,7 @@ export async function buildApp():Promise<FastifyInstance> {
   await app.register(authRoutes, { prefix: '/auth' });
   await app.register(profileRoutes, { prefix: '/api/profiles' });
   await app.register(cardRoutes, { prefix: '/api/cards' });
+  await app.register(publicCardRoutes);
   await app.register(publicRoutes, { prefix: '/api/u' });
   await app.register(followRoutes, { prefix: '/api/follow' });
   await app.register(connectRoutes, { prefix: '/api/connect' });

apps/backend/src/routes/publicCards.ts

@@ -0,0 +1,123 @@
+import type { FastifyInstance } from 'fastify';
+
+/**
+ * Public (unauthenticated) routes for DevCard profile sharing.
+ * These endpoints are intentionally open — no JWT required.
+ * Only safe, non-private fields are returned.
+ */
+export async function publicCardRoutes(fastify: FastifyInstance) {
+  /**
+   * GET /public/cards/:username
+   *
+   * Returns the default card for a given username.
+   * Used by the public profile page at /u/:username on the web app.
+   *
+   * Response shape:
+   * {
+   *   username: string
+   *   displayName: string | null
+   *   bio: string | null
+   *   avatarUrl: string | null
+   *   links: Array<{ platform: string; url: string; label: string | null }>
+   * }
+   */
+  fastify.get<{ Params: { username: string } }>(
+    "/public/cards/:username",
+    {
+      schema: {
+        params: {
+          type: "object",
+          required: ["username"],
+          properties: {
+            username: { type: "string" },
+          },
+        },
+        response: {
+          200: {
+            type: "object",
+            properties: {
+              username: { type: "string" },
+              displayName: { type: ["string", "null"] },
+              bio: { type: ["string", "null"] },
+              avatarUrl: { type: ["string", "null"] },
+              links: {
+                type: "array",
+                items: {
+                  type: "object",
+                  properties: {
+                    platform: { type: "string" },
+                    url: { type: "string" },
+                    label: { type: ["string", "null"] },
+                  },
+                },
+              },
+            },
+          },
+          404: {
+            type: "object",
+            properties: {
+              error: { type: "string" },
+            },
+          },
+        },
+      },
+    },
+    async (request, reply) => {
+      const { username } = request.params;
+
+      // Look up the user by their username (case-insensitive)
+      const user = await fastify.prisma.user.findFirst({
+        where: {
+          username: {
+            equals: username,
+            mode: 'insensitive',
+          },
+        },
+        select: {
+          username: true,
+          displayName: true,
+          bio: true,
+          avatarUrl: true,
+          // Fetch the user's default card and its platform links
+          cards: {
+            where: { isDefault: true },
+            take: 1,
+            select: {
+              cardLinks: {
+                orderBy: { displayOrder: 'asc' },
+                select: {
+                  platformLink: {
+                    select: {
+                      platform: true,
+                      url: true,
+                    },
+                  },
+                },
+              },
+            },
+          },
+        },
+      });
+
+      // 404 if user does not exist
+      if (!user) {
+        return reply.code(404).send({ error: 'User not found' });
+      }
+
+      const defaultCard = user.cards[0];
+
+      return reply.code(200).send({
+        username: user.username,
+        displayName: user.displayName ?? null,
+        bio: user.bio ?? null,
+        avatarUrl: user.avatarUrl ?? null,
+        links:
+          defaultCard?.cardLinks.map((link: { platformLink: { platform: string; url: string } }) => ({
+            platform: link.platformLink.platform,
+            url: link.platformLink.url,
+            label: null,
+          })) ?? [],
+      });
+    }
+  );
+}