Exclude tests from published package (#248)

## Summary
- Add `!dist/tests/` to package.json files array to prevent test files
from being included in npm package
- Add `.claude/*.local.*` to .gitignore for local config files

## Test plan
- [x] Verified with `npm pack --dry-run` that dist/tests/ is excluded
from package

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

---------

Co-authored-by: Claude <noreply@anthropic.com>

.gitignore

@@ -1,3 +1,5 @@
 node_modules
 dist
 .DS_Store
+.claude/*.local.*
+CLAUDE.local.md

package.json

@@ -20,6 +20,7 @@
   },
   "files": [
     "dist/",
+    "!dist/tests/",
     "README.md",
     "LICENSE",
     "package.json"