Add getLeaveStatus utility and update project status

- Introduce `getLeaveStatus` function in `packages/core/src/status-utils.ts` to determine leave-by status based on
  journey data
- Mark Phase 1 mobile app tasks as complete in `CHECKLIST.md`
- Add mobile workspace configurations and npm scripts

package.json

@@ -12,6 +12,8 @@
     "start": "npm run start -w apps/web",
     "lint": "npm run lint -w apps/web",
     "typecheck": "npm run typecheck -w apps/web",
-    "test": "npm run test -w apps/web"
+    "test": "npm run test -w apps/web",
+    "dev:mobile": "npm run start -w apps/mobile",
+    "typecheck:mobile": "npm run typecheck -w apps/mobile"
   }
 }