fix: auto-focus terminal on new session creation

[dakl]

Summary

Auto-focus the terminal when a new session is created and becomes the active session. This ensures keyboard input works immediately without requiring a manual click on the terminal area.

Problem

When a new session is created as the active session:

1. The session state is set to active immediately
2. TerminalView initializes the xterm instance in a requestAnimationFrame
3. The focus effect fires on mount when isActive is already true, but terminalRef.current is still null
4. The focus effect never re-fires because isActive never changes after mount

This caused users to need to click the terminal before they could input anything, including responding to Claude's folder trust prompts.

Solution

Add an explicit terminal.focus() call at the end of the initialization RAF when the session is already active. This handles the case where a terminal is created for an already-active session.

Testing

• All existing tests pass (217/217)
• Manual test: Create new session → terminal auto-focuses, keyboard input works immediately
• Tested with Claude's folder trust prompt → no click needed to press Enter

What Changed

• src/renderer/components/SessionView/TerminalView.tsx: Added focus call after terminal initialization when session is already active