chore(caddy): route pr-agent to Bun server (4023)

Cut-over pr-agent.asepharyana.my.id from the Python pr_agent server (4002)
to the Bun/TypeScript re-implementation (4023, pr-agent-bun.service).
Verified: webhook -> review -> LLM claude-opus-5 -> persistent comment
published (PR #19 nextjs-template).

infra/caddy/Caddyfile.prod

@@ -84,7 +84,7 @@ ai.asepharyana.my.id, ai.asepharyana.web.id {
 }
 
 pr-agent.asepharyana.my.id {
-	import proxy 4002
+	import proxy 4023
 }
 
 lidm.asepharyana.my.id {