feat: kit-connect + syno-balance SPK builds, busfleet hub registration endpoint

- kit-connect SPK (ipq806x): postinst with hub registration, start-stop-status,
  connect-daemon management, Tailscale + reverse SSH tunnel integration
- syno-balance SPK (noarch, test build): SmartWAN-aware dual-WAN load
  balancer with 6-factor scoring engine, syno-daemon lifecycle
- Busfleet hub: register.sh (port pool 2230-2299), Python HTTP server,
  systemd service, port-registry.json with x4078/x5925 assignments
- .gitignore: exclude SSH keys (*_id_ed25519), SPK artifacts (*.spk)

Gitea releases:
- kit-connect v0.1-0001 → x5925-kit-connect-v1 (production)
- syno-balance v0.1-0001 → syno-balance-test-v1 (prerelease)

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

syno-balance/scripts/postinst

@@ -0,0 +1,18 @@
+#!/bin/sh
+# syno-balance postinst — set up config, start daemon
+PKG_DIR="/var/packages/syno-balance/target"
+CONF="/etc/syno-balance/syno-balance.conf"
+LOG_TAG="syno-balance"
+
+log() { logger -t "$LOG_TAG" -p local0.warn "$*"; }
+
+mkdir -p /etc/syno-balance "$PKG_DIR/var"
+
+# If config doesn't exist, create from template
+if [ ! -f "$CONF" ]; then
+	cp "$PKG_DIR/etc/syno-balance.conf" "$CONF"
+	log "config created from template"
+fi
+
+log "postinst complete"
+exit 0