Agent validation screenshots are saved in unspecified locations

[derhally]

Problem

When the coding or testing agent takes screenshots during feature verification, the prompt templates don't specify where to store them. This results in screenshots being saved in arbitrary locations within the project directory, cluttering the workspace and potentially getting committed to version control.

Expected behavior

Validation artifacts (screenshots, etc.) should be saved to a well-known directory (.autoforge/validation) that is gitignored by default and documented as part of the project structure.