docs: add artifact POC analysis document (Fission-AI#398)

Add internal documentation for the artifact-based approach to OpenSpec
core. This document outlines design decisions, terminology, and the
philosophy behind treating dependencies as enablers rather than gates.

Author: TabishB

.gitignore

@@ -140,8 +140,6 @@ dist/
 vite.config.js.timestamp-*
 vite.config.ts.timestamp-*
 
-# Internal Docs
-docs/
 
 # Claude
 .claude/