PostgreSQL Installation Required for Local Development

[ai-yann]

What improvement(s) are you suggesting?

The error pg_config executable not found indicates that PostgreSQL needs to be installed locally before running make first-run. This should be clearly documented in the setup requirements.

This is already mentioned in the troubleshooting docs, but should be more prominent in the main setup flow (similar to my comment in this Issue):

4. **`pg_config` Executable Not Found:**
   - Ensure PostgreSQL is installed properly. For MacOS, use:
     ```bash
     brew install postgresql
     ```
   - Check [PostgreSQL documentation](https://www.postgresql.org/download/) for other OS instructions.

Additional information

No response