Prepare all packages for npm publishing

- Add author, repository, homepage, keywords, and engines fields to
  all 6 publishable package.json files
- Add README.md to react, tailwind-preset, and hex-background packages
- Add "type": "module" to web and react-native for consistency
- Rename web build script to .cjs for ESM package compatibility
- Remove overly broad "./dist/*" export from web package

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

packages/react/package.json

@@ -3,6 +3,26 @@
   "version": "0.1.0",
   "description": "React web components for the Dangerous Things design system",
   "license": "MIT",
+  "author": {
+    "name": "Dangerous Things",
+    "email": "info@dangerousthings.com"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/dangerous-tac0s/dt-design-system.git",
+    "directory": "packages/react"
+  },
+  "homepage": "https://github.com/dangerous-tac0s/dt-design-system#readme",
+  "keywords": [
+    "dangerousthings",
+    "design-system",
+    "react",
+    "components",
+    "theming"
+  ],
+  "engines": {
+    "node": ">=18.0.0"
+  },
   "type": "module",
   "exports": {
     ".": {