Document scratch documents directory in CLAUDE.md

Add guidelines for using .claude/ directory for scratch documents,
planning notes, and temporary files that should never be committed.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: jdalton

CLAUDE.md

@@ -264,6 +264,18 @@ Socket CLI integrates with:
 ### Package Detection
 - Use `existsSync()` not `fs.access()` for consistency
 
+## 📝 SCRATCH DOCUMENTS
+
+### Working Documents Directory
+- **Location**: `.claude/` directory (gitignored)
+- **Purpose**: Store scratch documents, planning notes, analysis reports, and temporary documentation
+- **🚨 CRITICAL**: NEVER commit files in `.claude/` to version control
+- **Examples of scratch documents**:
+  - Working notes and implementation plans
+  - Analysis reports from codebase investigations
+  - Temporary documentation and TODO lists
+  - Any files not intended for production use
+
 ---
 
 **For all other standards not covered here, refer to `socket-registry/CLAUDE.md` (in sibling repository)**