feat(agents): add public agent profile page at /agents/[id]

Implements a public-facing agent profile page with:
- Backend: new GET /agents/:agentId/profile public API endpoint with
  agent info, active listings, quality score, and review stats
- Frontend: server-rendered profile page with generateMetadata for SEO,
  JSON-LD structured data (RealEstateAgent schema), breadcrumbs
- Agent profile displays bio, service areas, quality score gauge,
  active listing cards, reviews with star ratings, and contact CTA
- Mobile responsive layout with sticky contact sidebar on desktop
- Vietnamese UI text throughout, consistent with existing patterns

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/web/lib/agents-server.ts

@@ -0,0 +1,67 @@
+/**
+ * Server-side agent data fetching for Next.js Server Components.
+ *
+ * Uses `fetch` directly (no browser-only helpers) so it can run
+ * inside `generateMetadata`, server pages, etc.
+ */
+
+import type { AgentPublicProfile, AgentReviewStats, PaginatedReviews } from './agents-api';
+
+const API_BASE_URL = process.env['NEXT_PUBLIC_API_URL'] || 'http://localhost:3001/api/v1';
+
+/**
+ * Fetch a public agent profile by ID — server-only.
+ * Returns `null` when the agent is not found (404) so callers can `notFound()`.
+ */
+export async function fetchAgentProfile(agentId: string): Promise<AgentPublicProfile | null> {
+  try {
+    const res = await fetch(`${API_BASE_URL}/agents/${agentId}/profile`, {
+      next: { revalidate: 300 }, // ISR: re-validate every 5 min
+    });
+
+    if (!res.ok) return null;
+    return (await res.json()) as AgentPublicProfile;
+  } catch {
+    return null;
+  }
+}
+
+/**
+ * Fetch reviews for an agent — server-only.
+ */
+export async function fetchAgentReviews(
+  agentId: string,
+  page = 1,
+  limit = 10,
+): Promise<PaginatedReviews> {
+  try {
+    const res = await fetch(
+      `${API_BASE_URL}/reviews?targetType=AGENT&targetId=${agentId}&page=${page}&limit=${limit}`,
+      { next: { revalidate: 300 } },
+    );
+
+    if (!res.ok) {
+      return { data: [], total: 0, page: 1, limit: 10, totalPages: 0 };
+    }
+    return (await res.json()) as PaginatedReviews;
+  } catch {
+    return { data: [], total: 0, page: 1, limit: 10, totalPages: 0 };
+  }
+}
+
+/**
+ * Fetch review stats for an agent — server-only.
+ */
+export async function fetchAgentReviewStats(agentId: string): Promise<AgentReviewStats | null> {
+  try {
+    const res = await fetch(
+      `${API_BASE_URL}/reviews/stats?targetType=AGENT&targetId=${agentId}`,
+      { next: { revalidate: 300 } },
+    );
+
+    if (!res.ok) return null;
+    return (await res.json()) as AgentReviewStats;
+  } catch {
+    return null;
+  }
+}