fix(npm): Windows postinstall file locking issue (GH#670)

- Move write stream creation after redirect handling to avoid orphan
  streams that keep file handles open
- Add 100ms delay after file.close() on Windows to ensure handle release
- Fixes "The process cannot access the file" error during extraction

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

CHANGELOG.md

@@ -83,6 +83,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   - Skips interactions.jsonl and molecules.jsonl in sync checks
   - These files are runtime state, not sync targets
 
+- **Windows npm postinstall file locking** (GH#670) - Windows install fix
+  - Fixed file handle not being released before extraction on Windows
+  - Moved write stream creation after redirect handling to avoid orphan streams
+  - Added delay after file close to ensure Windows releases file handle
+
 - **FatalErrorRespectJSON** (bd-28sq) - Consistent error output
   - All commands respect `--json` flag for error output
   - Errors return proper JSON structure when flag is set