[Feature] Implement Mandatory "Discovery Gate" to Prevent Redundant File Creation #1448
Description
Agents often generate brand-new files for features that already exist in the codebase (e.g., creating WorkflowEditor.tsx when WorkflowCanvas.tsx is already present). This leads to code duplication, broken routing, and high technical debt.
The current speckit.plan.md and speckit.specify.md workflows do not explicitly force the AI agent to perform a global search of the @src directory before defining new technical designs. The agent defaults to "creation" rather than "refactoring."