spec init — initialize or extend a project

CLI at scripts/specctl. Three modes, picked by checking whether .spec/ exists and whether the user passed a file path.

Step 1: Check existing

ls .spec/ 2>/dev/null && echo "SPEC_EXISTS"

Mode A: New project (no .spec/)

Step 2: Brainstorm

If a brainstorming workflow is available in the runtime, use it to surface requirements. Otherwise ask the user directly: