Add workspace index and developer-specific journals for AI sessions

- Created a main workspace index to track AI Agent work records across developers.
- Added a personal index for developer 'yuxuanhui' with current status and session history.
- Initialized the first journal file for 'yuxuanhui' to document AI development sessions.
- Introduced AGENTS.md for Trellis instructions, detailing project structure and usage guidelines.

.trellis/spec/frontend/hook-guidelines.md

@@ -0,0 +1,51 @@
+# Hook Guidelines
+
+> How hooks are used in this project.
+
+---
+
+## Overview
+
+<!--
+Document your project's hook conventions here.
+
+Questions to answer:
+- What custom hooks do you have?
+- How do you handle data fetching?
+- What are the naming conventions?
+- How do you share stateful logic?
+-->
+
+(To be filled by the team)
+
+---
+
+## Custom Hook Patterns
+
+<!-- How to create and structure custom hooks -->
+
+(To be filled by the team)
+
+---
+
+## Data Fetching
+
+<!-- How data fetching is handled (React Query, SWR, etc.) -->
+
+(To be filled by the team)
+
+---
+
+## Naming Conventions
+
+<!-- Hook naming rules (use*, etc.) -->
+
+(To be filled by the team)
+
+---
+
+## Common Mistakes
+
+<!-- Hook-related mistakes your team has made -->
+
+(To be filled by the team)