fix: resolve "Failed to get session title" error in packaged macOS app

[tianrking]

After packaging for macOS, the app would fail with "Failed to get session title" error when creating new sessions, preventing normal operation.

The issue was caused by accessing Electron's app.isPackaged property at module load time, which fails in the packaged environment:

• export const claudeCodePath = getClaudeCodePath() was called during module initialization
• app.getPath("userData") was called at module level in ipc-handlers.ts
• app.on() event handlers were registered at module level in main.ts

1. util.ts: Delay getClaudeCodePath() call to runtime within generateSessionTitle() function instead of module-level constant
2. runner.ts: Use getClaudeCodePath() function call instead of importing constant
3. ipc-handlers.ts: Delay sessions initialization with initializeSessions() function
4. main.ts: Move event handler registration inside app.on("ready") callback
5. Add comprehensive error handling with fallback to simple title generation

• Update README.md and README_ZH.md to correct build commands (dist:mac-arm64 and dist:mac-x64 instead of non-existent dist:mac)

[tianrking]

hola ping @wksantiago @Pactortester

[tianrking]

@aiagentbuilder