Improve apps (#19256)

- simplify the base application template
- remove --exhaustive option and replace by a --example option like in
next.js https://nextjs.org/docs/app/api-reference/cli
- Fix some bugs and logs
- add a post-card app in twenty-apps/examples/

packages/twenty-apps/examples/hello-world/src/fields/example-field.ts

@@ -0,0 +1,11 @@
+import { defineField, FieldType } from 'twenty-sdk';
+import { EXAMPLE_OBJECT_UNIVERSAL_IDENTIFIER } from 'src/objects/example-object';
+
+export default defineField({
+  objectUniversalIdentifier: EXAMPLE_OBJECT_UNIVERSAL_IDENTIFIER,
+  universalIdentifier: 'be08a7c6-2586-4d91-9fa7-0a44e6eae30c',
+  type: FieldType.NUMBER,
+  name: 'priority',
+  label: 'Priority',
+  description: 'Priority level for the example item (1-10)',
+});