feat(hooks): enable tool-output-truncator by default

Enable tool-output-truncator hook by default instead of requiring experimental config opt-in. Users can disable it via disabled_hooks if needed.

Changes:
- Add tool-output-truncator to HookNameSchema
- Remove tool_output_truncator from ExperimentalConfigSchema
- Update all README files (EN, KO, JA, ZH-CN)

🤖 GENERATED WITH ASSISTANCE OF [OhMyOpenCode](https://github.com/code-yeongyu/oh-my-opencode)

src/index.ts

@@ -255,7 +255,7 @@ const OhMyOpenCodePlugin: Plugin = async (ctx) => {
   const commentChecker = isHookEnabled("comment-checker")
     ? createCommentCheckerHooks(pluginConfig.comment_checker)
     : null;
-  const toolOutputTruncator = pluginConfig.experimental?.tool_output_truncator === true
+  const toolOutputTruncator = isHookEnabled("tool-output-truncator")
     ? createToolOutputTruncatorHook(ctx, { experimental: pluginConfig.experimental })
     : null;
   const directoryAgentsInjector = isHookEnabled("directory-agents-injector")