fix: audit gaps — GL local keyword, key authorization in wizards, register script parity

GL daemon: removed remaining 'local ts_ip' (busybox ash compat)
Synology wizard: auto-authorizes tunnel key via POST /api/authorize-key
GL wizard: same key authorization flow added
Synology: added connect-register.sh for parity with GL
syno-balance build.sh: removed deprecated checksum file (same lesson as kit-connect)

All four curl hubs (wizards + register scripts) now have --max-time 15.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

gl-kit-connect/files/usr/sbin/connect-daemon.sh

@@ -78,7 +78,6 @@ start_tailscale() {
 		--accept-routes=false \
 		--accept-dns=false 2>&1 | while read -r line; do log "tailscale: $line"; done
 
-	local ts_ip
 	ts_ip=$("$TAILSCALE_BIN" ip -4 2>/dev/null || echo "unknown")
 	log "tailscale: connected — IP=${ts_ip}"
 }