fix: prevent plugin crash by removing non-function exports from barrel files

BREAKING: OpenCode plugin loader calls all exports as functions.
Exporting non-function values (schemas, constants, types) causes TypeError.

Changes:
- Remove OhMyOpenCodeConfigSchema export from root index.ts
- Replace 'export *' with explicit function exports in hooks/index.ts
- Remove 'export *' from comment-checker/index.ts

package.json

@@ -1,6 +1,6 @@
 {
   "name": "oh-my-opencode",
-  "version": "0.1.2",
+  "version": "0.1.3",
   "description": "OpenCode plugin - custom agents (oracle, librarian) and enhanced features",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",