fix: Move zod from dependencies to peerDependencies

Zod should be a peer dependency so consumers control the version,
avoiding conflicts. This package now accepts zod ^3.0.0 || ^4.0.0.

- Removed zod from dependencies
- Added zod to peerDependencies with broad version range
- Added zod to devDependencies for development
- Marked zod as optional in peerDependenciesMeta

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: scalvert

package-lock.json

@@ -76,8 +76,7 @@
     "rehype-remark": "^10.0.0",
     "remark-gfm": "^4.0.0",
     "remark-stringify": "^11.0.0",
-    "unified": "^11.0.0",
-    "zod": "^4.3.6"
+    "unified": "^11.0.0"
   },
   "devDependencies": {
     "@docusaurus/core": "^3.9.2",
@@ -98,13 +97,15 @@
     "tsup": "^8.0.0",
     "typescript": "^5.0.0",
     "typescript-eslint": "^8.53.1",
-    "vitest": "^4.0.18"
+    "vitest": "^4.0.18",
+    "zod": "^4.3.6"
   },
   "peerDependencies": {
     "@docusaurus/core": "^3.0.0",
     "@docusaurus/types": "^3.0.0",
     "react": "^18.0.0 || ^19.0.0",
-    "react-dom": "^18.0.0 || ^19.0.0"
+    "react-dom": "^18.0.0 || ^19.0.0",
+    "zod": "^3.0.0 || ^4.0.0"
   },
   "peerDependenciesMeta": {
     "@docusaurus/core": {
@@ -115,6 +116,9 @@
     },
     "react-dom": {
       "optional": true
+    },
+    "zod": {
+      "optional": true
     }
   },
   "engines": {