feat: Add guideline to prefer code generation tools over manual coding

Author: cephalization

src/plan.ts

@@ -50,6 +50,7 @@ NOTE:
 - Distinguish between frontend and backend tooling. 
 - For frontend tooling, check if 'agent-browser' cli is installed. If so, it should be used for validating visual changes.
 - Distinguish between unit tests and integration tests.
+- Prefer code generation tools over manual coding when there are scripts to generate code (e.g. relay, openapi-codegen, etc).
 
 ## Step 2: Plan the Tasks