- Fixed double-emission bug in network_manager.gd: ENet signal connections
(peer_connected/peer_disconnected) are now only connected when netfox
NetworkEvents is NOT available, preventing duplicate player_connected/
player_disconnected signal emissions.
- Fixed stop() to only disconnect ENet signals when they were actually
connected (mirrors the conditional connection in start_server()).
- Fixed headless parse error in player_net_input.gd: replaced direct
NetworkTime.before_tick_loop reference with Engine.get_singleton()
call, avoiding unresolved type identifier in headless mode.
- netfox_bootstrap.gd added as minimal autoload placeholder.
- Dual-path architecture: netfox NetworkEvents when available (editor),
ENet fallback when netfox unavailable (headless server).
- Broadcast RPCs (spawn, round state, scores) kept as-is since they
work identically through Godot's MultiplayerAPI in both paths.
