add the tRPC hello world example

Signed-off-by: Oleg S <97077423+RobotSail@users.noreply.github.com>

packages/catalog-model/examples/apis/hello-world-trpc-api.yaml

@@ -0,0 +1,25 @@
+apiVersion: backstage.io/v1alpha1
+kind: API
+metadata:
+  name: hello-world-trpc
+  description: Hello World example for tRPC
+spec:
+  type: trpc
+  lifecycle: experimental
+  owner: team-c
+  definition: |
+    import { z } from 'zod';
+    import { publicProcedure, router } from '../trpc';
+    
+    export const apiRouter = router({
+      version: publicProcedure.query(() => {
+        return { version: '0.42.0' };
+      }),
+      hello: publicProcedure
+        .input(z.object({ username: z.string().nullish() }).nullish())
+        .query(({ input, ctx }) => {
+          return {
+            text: `hello ${input?.username ?? ctx.user?.name ?? 'world'}`,
+          };
+        }),
+    });