chore: fix release script and ignore .claude (#40)

- `release` script was `npm build & npm publish`: `npm build` is not a
  built-in npm command (should be `npm run build`), and the single `&`
  ran the two commands in parallel, so `npm publish` could fire before
  the build completed (or even when it failed). Replaced with
  `npm run build && npm publish` so publish is gated on build success.
- Added `.claude` to `.gitignore` so local Claude Code context files
  (CLAUDE.md, etc.) stay out of the repo.

Author: iifawzi

.gitignore

@@ -4,6 +4,7 @@ node_modules
 dist
 
 .vscode
+.claude
 package-lock.json
 testing.ts
 coverage

package.json

@@ -32,7 +32,7 @@
     "test:unit": "jest tests/unit",
     "test:e2e": "jest tests/e2e",
     "test:coverage": "jest --coverage",
-    "release": "npm build & npm publish"
+    "release": "npm run build && npm publish"
   },
   "_moduleAliases": {
     "@": "dist"