feat: add event log panel, Chinese font support, and documentation

- Add EventLog.cs: scrollable event log panel showing game events
  - Color-coded entries for different event types
  - Toggle visibility, clear button, timestamps
  - Auto-scroll to newest entries

- Add Chinese font support (Source Han Sans SC)
  - SourceHanSansSC-Regular.otf font file
  - ChineseFontSetup.cs editor tool for TMP font asset generation
  - Configure as fallback font for TextMeshPro

- Fix particle system velocity curve warnings in WeatherEffects.cs
  - Ensure all velocity axes use consistent curve mode

- Add comprehensive README.md with project documentation
  - Architecture overview, features, tech stack
  - Quick start guide, Unity client structure
  - Communication protocol, development notes

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

unity-client/ProjectSettings/ProjectSettings.asset

@@ -165,7 +165,8 @@ PlayerSettings:
   androidSupportedAspectRatio: 1
   androidMaxAspectRatio: 2.4
   androidMinAspectRatio: 1
-  applicationIdentifier: {}
+  applicationIdentifier:
+    Standalone: com.DefaultCompany.unity-client
   buildNumber:
     Standalone: 0
     VisionOS: 0