Add Phase 3 connectivity modules — 8 modules + bridge scripts

WireGuard (primary C2, PersistentKeepalive=0 for zero idle traffic),
Tailscale (fallback mesh VPN), Bridge (transparent inline L2 bridge with
802.1X bypass and ebtables protocol suppression), WiFiClient (WPA2-PSK
and WPA2-Enterprise via wpa_supplicant), ReverseTunnel (autossh over
stunnel/websocket — never raw SSH on 443), CellularBackup (LTE modem
via AT commands/mmcli, OPi Zero 3+ only), BLEEmergency (GATT server
with PSK auth for local last-resort access), DataExfil (priority-based
exfil with IMMEDIATE/NIGHTLY/ON_DEMAND tiers through connectivity chain).

Bridge scripts: setup_bridge.sh (create br0, disable STP, suppress
CDP/LLDP/BPDU via ebtables) and teardown_bridge.sh (safe cleanup).

modules/connectivity/__init__.py

@@ -0,0 +1,21 @@
+"""BigBrother connectivity modules — C2 and data transport layer."""
+
+from modules.connectivity.wireguard import WireGuard
+from modules.connectivity.tailscale import Tailscale
+from modules.connectivity.bridge import Bridge
+from modules.connectivity.wifi_client import WiFiClient
+from modules.connectivity.reverse_tunnel import ReverseTunnel
+from modules.connectivity.cellular_backup import CellularBackup
+from modules.connectivity.ble_emergency import BLEEmergency
+from modules.connectivity.data_exfil import DataExfil
+
+__all__ = [
+    "WireGuard",
+    "Tailscale",
+    "Bridge",
+    "WiFiClient",
+    "ReverseTunnel",
+    "CellularBackup",
+    "BLEEmergency",
+    "DataExfil",
+]