chore: add AGPL-3.0 license and update package.json license fields

Co-authored-by: Flea Flicker <flea-flicker@paperclip.ing>
Co-authored-by: Paperclip <noreply@paperclip.ing>

apps/api/package.json

@@ -35,5 +35,6 @@
     "typescript": "^5.7.3",
     "typescript-eslint": "^8.20.0",
     "vitest": "^3.2.4"
-  }
+  },
+  "license": "AGPL-3.0-only"
 }

apps/e2e/package.json

@@ -10,5 +10,6 @@
   },
   "devDependencies": {
     "@playwright/test": "^1.50.1"
-  }
+  },
+  "license": "AGPL-3.0-only"
 }

apps/web/package.json

@@ -36,5 +36,6 @@
     "vite": "^6.0.7",
     "vite-plugin-pwa": "^0.21.1",
     "vitest": "^3.0.4"
-  }
+  },
+  "license": "AGPL-3.0-only"
 }