fix(docker): always reinstall sensor-proxy to refresh tokens/config

Same turnkey UX issue as PVE quick setup: when local sensor-proxy socket
exists and validates, install-docker.sh would skip reinstallation (line 498).
This left stale control-plane tokens and URLs.

Fix: Always reinstall when LOCAL_PROXY_EXISTED_AT_START=true
- Track socket existence at script start
- Change message: 'will refresh to update tokens/config'
- Set SKIP_INSTALLATION=false to force reinstall
- Installer is idempotent (Phase 2), safe to rerun

This completes the turnkey repair fix across all entry points (PVE quick
setup and Docker installer).

scripts/install-docker.sh

@@ -464,6 +464,7 @@ BIND_MOUNT_SOCKET="/mnt/pulse-proxy/pulse-sensor-proxy.sock"
 LOCAL_SOCKET="/run/pulse-sensor-proxy/pulse-sensor-proxy.sock"
 SOCKET_PATH=""
 SKIP_INSTALLATION=false
+LOCAL_PROXY_EXISTED_AT_START=false
 
 echo "Checking for existing pulse-sensor-proxy..."
 echo ""
@@ -492,10 +493,12 @@ fi
 # Check for existing local installation
 if [ -S "$LOCAL_SOCKET" ] && [ "$SKIP_INSTALLATION" = false ]; then
     echo "  Found socket at /run/pulse-sensor-proxy (local installation)"
+    LOCAL_PROXY_EXISTED_AT_START=true
     if validate_socket "$LOCAL_SOCKET"; then
-        echo "  ✓ Socket is functional"
+        echo "  ✓ Socket is functional - will refresh to update tokens/config"
         SOCKET_PATH="/run/pulse-sensor-proxy"
-        SKIP_INSTALLATION=true
+        # Don't skip installation - always reinstall to refresh tokens
+        SKIP_INSTALLATION=false
     else
         echo "  ⚠️  Socket exists but is not responsive - will reinstall"
         systemctl stop pulse-sensor-proxy 2>/dev/null || true