wiqd agent eval init conflicts with the eval file created by agent scaffolding

Observed with WIQD 0.12.2 on Windows.

Problem

A newly scaffolded declarative-agent project already contains evals/prompts.json, but the
documented wiqd agent eval init workflow assumes that it can initialize that file. The two WIQD
workflows therefore conflict on a fresh project.

Steps to reproduce

1. Scaffold a base declarative-agent project:

   wiqd agent create --name eval-init-test --output ./eval-init-test
   

2. Enter the generated project directory.

3. Confirm that evals/prompts.json already exists.

4. Run:

   wiqd agent eval init --env local
   

Actual behavior

The command exits with code 2:

Eval prompts file already exists at 'evals/prompts.json'. Edit it directly or delete it first.

This happens immediately on a project created by WIQD itself, before the user has initialized or
edited the evaluation suite.

Expected behavior

The scaffold and eval-initialization workflows should compose cleanly. Possible resolutions include:

• make eval init idempotent and validate or update the scaffolded starter;
• do not pre-create evals/prompts.json during agent scaffolding;
• have eval init recognize the scaffolded starter as already initialized and return success with
  clear guidance; or
• document that eval init is unnecessary for newly scaffolded projects.

Current workaround

Run eval init with an alternate --output path to obtain the current authoritative starter
schema, inspect it, manually edit the original scaffolded evals/prompts.json, and then delete the
alternate file.

Environment

Reproduce the conflict with wiqd agent create and wiqd agent eval init --env local on Windows, then inspect how scaffolding creates evals/prompts.json and how eval initialization handles an existing file. Compare the generated starter with the authoritative schema from an alternate --output path. Done means a freshly scaffolded project and the documented eval workflow compose cleanly with clear behavior.