feat(hooks): add sisyphus-gpt-hephaestus-reminder hook

Shows error toast when Sisyphus runs with a GPT model, nudging user to
use Hephaestus instead.

🤖 Generated with [OhMyOpenCode](https://github.com/code-yeongyu/oh-my-opencode)

src/hooks/index.ts

@@ -27,6 +27,7 @@ export { createInteractiveBashSessionHook } from "./interactive-bash-session";
 export { createThinkingBlockValidatorHook } from "./thinking-block-validator";
 export { createCategorySkillReminderHook } from "./category-skill-reminder";
 export { createRalphLoopHook, type RalphLoopHook } from "./ralph-loop";
+export { createSisyphusGptHephaestusReminderHook } from "./sisyphus-gpt-hephaestus-reminder";
 export { createAutoSlashCommandHook } from "./auto-slash-command";
 export { createEditErrorRecoveryHook } from "./edit-error-recovery";
 export { createJsonErrorRecoveryHook } from "./json-error-recovery";