fix: use ESM Tauri event listeners

[chaochaoweb3]

Summary

• replace runtime require() calls for @tauri-apps/api/event with ESM imports
• keep the existing DOM event fallback for non-Tauri web mode
• apply the same fix to ClaudeCodeSession and useClaudeMessages

Validation

• npm exec tsc -- --noEmit
• npm run build
• git diff --check
• rg -n "require('@tauri-apps/api/event')|require("@tauri-apps/api/event")" src/components/ClaudeCodeSession.tsx src/components/claude-code-session/useClaudeMessages.ts

Fixes #462