docs: add local testing instructions for NPM distribution

Add a detailed guide to CLAUDE.md on how to build, pack, and test the
NPM package locally without requiring a full release.

Co-Authored-By: Grey Newell <greyshipscode@gmail.com>
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: greynewell

CLAUDE.md

@@ -30,6 +30,35 @@ When creating a GitHub issue, always include `@claude` at the end of the body so
 - Lint: `go vet ./...`
 - No test suite yet — at minimum verify `go build ./...` passes before committing
 
+### Testing NPM Distribution Locally
+
+To test the one-command installation flow without releasing:
+
+1. **Build the latest binary** into the `npm` directory:
+   ```bash
+   mkdir -p npm/bin && go build -o npm/bin/uncompact .
+   ```
+
+2. **Package and install locally**:
+   ```bash
+   npm pack
+   # Replace 0.0.0 with the version in package.json if different
+   npm install -g ./uncompact-0.0.0.tgz --foreground-scripts
+   ```
+   *Note: `--foreground-scripts` is required to see the output of the post-install hook.*
+
+3. **Verify installation**:
+   ```bash
+   uncompact verify-install
+   uncompact status
+   ```
+
+4. **Total Cleanup** (to reset your environment):
+   ```bash
+   uncompact uninstall --total
+   npm uninstall -g uncompact
+   ```
+
 ## Commits
 
 Always include both co-authors in every commit message: