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

src/hooks/index.ts

@@ -1,5 +1,5 @@
-export * from "./todo-continuation-enforcer"
-export * from "./context-window-monitor"
-export * from "./session-notification"
-export * from "./session-recovery"
-export * from "./comment-checker"
+export { createTodoContinuationEnforcer } from "./todo-continuation-enforcer"
+export { createContextWindowMonitorHook } from "./context-window-monitor"
+export { createSessionNotification } from "./session-notification"
+export { createSessionRecoveryHook } from "./session-recovery"
+export { createCommentCheckerHooks } from "./comment-checker"