Allow setting Remote Control session name from CLI via --session-name flag

Problem

When starting multiple Claude Code CLI sessions with Remote Control, the Code panel auto-generates session names from conversation content or hostname. While the mobile app supports manual rename, this requires:

1. Open the app
2. Long-press the session
3. Manually rename each one

This is tedious when launching multiple sessions, and the auto-generated names are meaningless before any conversation starts (e.g., "tims-macbook-pro-4-local-transient...").

Proposed Solution

Add a --session-name flag so users can set a meaningful name at launch time:

claude --session-name "food-delivery-backend"
claude --session-name "frontend-react"

This would set the display name shown in the Code panel immediately, eliminating the need to manually rename in the app after each session starts.

Current Workaround

Long-press the session in the mobile app → Rename. Works but requires manual effort for every new session.