fix: add centralized error handler for unhandled exceptions

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/server/index.ts

@@ -18,6 +18,16 @@ seedDefaults();
 
 const app = new Hono();
 
+// Centralized error handler
+app.onError((err, c) => {
+	console.error(`[${c.req.method}] ${c.req.path}:`, err);
+	const message =
+		process.env.NODE_ENV === "production"
+			? "Internal server error"
+			: err.message || "Internal server error";
+	return c.json({ error: message }, 500);
+});
+
 // Health check
 app.get("/api/health", (c) => {
 	return c.json({ status: "ok" });