Prepare cladm for npm publishing

Add files field, author, repository, and engines to package.json. Add
.npmignore, MIT LICENSE file, GitHub Actions publish workflow on v* tags,
and update README install section with bun install -g / bunx instructions.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.github/workflows/publish.yml

@@ -0,0 +1,22 @@
+name: Publish to npm
+
+on:
+  push:
+    tags:
+      - "v*"
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: oven-sh/setup-bun@v2
+        with:
+          bun-version: latest
+
+      - run: bun install
+
+      - run: npm publish
+        env:
+          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}