Add hackathon banner and feature 8004/x402 on home page (#2134)

Add a site-wide dismissible banner promoting the "Build Agents for the
Real World" Celo Hackathon (Feb 6–15). Add an "AI Agent Infrastructure"
section to the home page featuring ERC-8004 Agent Trust and x402 Agent
Payments cards.

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: viral-sangani

docs.json

@@ -19,6 +19,10 @@
   "appearance": {
     "default": "dark"
   },
+  "banner": {
+    "content": "🤖 **Build Agents for the Real World** — Celo Hackathon (Feb 6–15)! [Join now →](https://celoplatform.notion.site/Build-Agents-for-the-Real-World-Celo-Hackathon-2fdd5cb803de80c99010c04b6902a3a9)",
+    "dismissible": true
+  },
   "fonts": {
     "heading": {
       "family": "system-ui"

home/celo.mdx

@@ -26,6 +26,17 @@ description: "Celo is a leading Ethereum L2. As the frontier chain for global im
   </Card>
 </CardGroup>
 
+## AI Agent Infrastructure
+
+<CardGroup cols={2}>
+  <Card title="ERC-8004: Agent Trust" icon="shield-check" href="/build-on-celo/build-with-ai/8004">
+    Establish trust infrastructure for autonomous AI agents with identity, reputation, and validation registries.
+  </Card>
+  <Card title="x402: Agent Payments" icon="money-bill-transfer" href="/build-on-celo/build-with-ai/x402">
+    Enable instant, permissionless micropayments for AI agents using stablecoins via HTTP 402.
+  </Card>
+</CardGroup>
+
 ## Builder Support
 
 <CardGroup cols={2}>