Remove 5 test setting IDs that were incorrectly added to the production
apiSchema.ts. Test settings now use `as TestSettingId` casts in test
files instead of polluting the production Settings type.
Changes:
- Remove TestSetting, TestHiddenSetting, TestDeprecatedSetting,
TestVisibleSetting, Comfy.TestSetting from apiSchema.ts
- Add TestSettingId type helper to extensionAPI.spec.ts and
useSettingSearch.spec.ts
- Use specific `as TestSettingId` casts with explanatory comments
This keeps production types clean while allowing tests to register
arbitrary setting IDs (which is valid extension behavior).
Amp-Thread-ID: https://ampcode.com/threads/T-019c1833-2352-728b-a523-a8f440fd3ba1
Co-authored-by: Amp <amp@ampcode.com>