1750 extensibility twenty sdk v2 use twenty sdk to define an object (#15230)

We maintain jsonc object definition but will deprecate them pretty soon

## Before
<img width="1512" height="575" alt="image"
src="https://github.com/user-attachments/assets/d2fa6ca4-c456-4aa9-a1e3-845b61839718"
/>

## After
<img width="1260" height="555" alt="image"
src="https://github.com/user-attachments/assets/ba72f4cf-d443-4967-913c-029bc71f3f48"
/>

packages/twenty-apps/hello-world/objects/post-card/object.manifest.jsonc

@@ -1,9 +0,0 @@
-{
-  "$schema": "https://raw.githubusercontent.com/twentyhq/twenty/main/packages/twenty-cli/schemas/object.schema.json",
-  "universalIdentifier": "54b589ca-eeed-4950-a176-358418b85c05",
-  "standardId": "54b589ca-eeed-4950-a176-358418b85c05",
-  "nameSingular": "postCard",
-  "namePlural": "postCards",
-  "labelSingular": "Post card",
-  "labelPlural": "Post cards"
-}

packages/twenty-apps/hello-world/package.json

@@ -19,7 +19,8 @@
     }
   },
   "dependencies": {
-    "axios": "^1.12.2"
+    "axios": "^1.12.2",
+    "twenty-sdk": "^0.0.2"
   },
   "devDependencies": {
     "@types/node": "^24.7.2"

packages/twenty-apps/hello-world/src/postCard.ts

@@ -0,0 +1,10 @@
+import { ObjectMetadata } from 'twenty-sdk';
+
+@ObjectMetadata({
+  universalIdentifier: '54b589ca-eeed-4950-a176-358418b85c05',
+  nameSingular: 'postCard',
+  namePlural: 'postCards',
+  labelSingular: 'Post card',
+  labelPlural: 'Post cards',
+})
+export class PostCard {}

packages/twenty-apps/hello-world/tsconfig.json

@@ -0,0 +1,22 @@
+{
+  "compileOnSave": false,
+  "compilerOptions": {
+    "sourceMap": true,
+    "declaration": true,
+    "outDir": "./dist",
+    "rootDir": ".",
+    "moduleResolution": "node",
+    "emitDecoratorMetadata": true,
+    "experimentalDecorators": true,
+    "importHelpers": true,
+    "strict": true,
+    "target": "es2018",
+    "module": "esnext",
+    "lib": ["es2020", "dom"],
+    "skipLibCheck": true,
+    "skipDefaultLibCheck": true,
+    "resolveJsonModule": true
+  },
+  "exclude": ["node_modules", "dist"],
+  "include": ["**/*.ts"]
+}

packages/twenty-apps/hello-world/yarn.lock

@@ -5,11 +5,22 @@ __metadata:
   version: 8
   cacheKey: 10c0
 
+"@types/node@npm:^24.7.2":
+  version: 24.9.1
+  resolution: "@types/node@npm:24.9.1"
+  dependencies:
+    undici-types: "npm:~7.16.0"
+  checksum: 10c0/c52f8168080ef9a7c3dc23d8ac6061fab5371aad89231a0f6f4c075869bc3de7e89b075b1f3e3171d9e5143d0dda1807c3dab8e32eac6d68f02e7480e7e78576
+  languageName: node
+  linkType: hard
+
 "Hello world@workspace:.":
   version: 0.0.0-use.local
   resolution: "Hello world@workspace:."
   dependencies:
+    "@types/node": "npm:^24.7.2"
     axios: "npm:^1.12.2"
+    twenty-sdk: "npm:^0.0.2"
   languageName: unknown
   linkType: soft
 
@@ -246,3 +257,17 @@ __metadata:
   checksum: 10c0/fe7dd8b1bdbbbea18d1459107729c3e4a2243ca870d26d34c2c1bcd3e4425b7bcc5112362df2d93cc7fb9746f6142b5e272fd1cc5c86ddf8580175186f6ad42b
   languageName: node
   linkType: hard
+
+"twenty-sdk@npm:^0.0.2":
+  version: 0.0.2
+  resolution: "twenty-sdk@npm:0.0.2"
+  checksum: 10c0/99e6fe86059d847b548c1f03e0f0c59a4d540caf1d28dd4500f1f5f0094196985ded955801274de9e72ff03e3d1f41e9a509b4c2c5a02ffc8a027277b1e35d8e
+  languageName: node
+  linkType: hard
+
+"undici-types@npm:~7.16.0":
+  version: 7.16.0
+  resolution: "undici-types@npm:7.16.0"
+  checksum: 10c0/3033e2f2b5c9f1504bdc5934646cb54e37ecaca0f9249c983f7b1fc2e87c6d18399ebb05dc7fd5419e02b2e915f734d872a65da2e3eeed1813951c427d33cc9a
+  languageName: node
+  linkType: hard