Beta deploy automation: beta app connection triggers Pi branch switch

Overview

When opening the beta TestFlight build of PitMissionController, the app should automatically trigger the Pi server to switch to the ground-control branch and restart — no manual SSH or deploy steps needed.

Flow

1. Beta app connects to the existing WebSocket server (running on main)
2. During handshake it sends a {"type": "betaHandshake"} message
3. Server detects it's a beta client, spawns a background subprocess:

   git checkout ground-control && git pull && cd CartInformationDisplays/frontend && npm run build && sudo systemctl restart missionControlServer.service
   

4. Server restarts (~5–10s), now on ground-control
5. App auto-reconnects (reconnect logic already exists in WebsocketEngine.swift)

Switching back to production works in reverse — the production build sends a prodHandshake, server redeploys main.

Implementation notes

• WebSocketManager.reconnect() already handles reconnection with a 2s delay, so no iOS changes needed for the reconnect behavior
• On reconnect, stateL/stateR reset to .Screensaver — expected behavior during a deliberate deploy
• Guard: only trigger the deploy if the server isn't already on the target branch (git branch --show-current) to avoid redundant redeploys when opening the app multiple times
• The Pi's IP is stable at 192.168.105.10 on the competition hotspot, so the endpoint is persistent — no Remote.it or dynamic DNS needed

Files to change

• CartInformationDisplays/main.py (or relevant routing file) — add betaHandshake / prodHandshake message handlers that spawn the deploy subprocess
• PitMissionController/RequestRouter.swift — send betaHandshake on connect (for beta build; prodHandshake for production build)
• Deploy script on Pi — git checkout <branch> && git pull && npm run build && systemctl restart

Start with CartInformationDisplays/main.py and PitMissionController/RequestRouter.swift, then review the existing WebsocketEngine.swift reconnect behavior. Trace the handshake path and the Pi deploy script, including the target-branch guard. Done means beta and production handshakes trigger the appropriate deployment and the app reconnects after the server restart.