Phase 7: netfox + godot-jolt stack upgrade

Stack installed:
- netfox v1.35.3 (core + extras + noray + internals)
- godot-jolt v0.16.0-stable

Architecture:
- Server: ENet transport (works headless, no netfox deps)
- Client/Editor: netfox rollback (RollbackSynchronizer, TickInterpolator)

New/modified:
- docs/migration-netfox-plan.md — migration architecture
- scripts/network/network_manager.gd — netfox-aware ENet fallback
- scripts/network/player.gd — clean base player
- client/characters/player_netfox.gd — rollback player w/ WeaponManager
- client/characters/input/player_net_input.gd — BaseNetInput subclass
- client/characters/character/fps_character_controller.gd — netfox input feed
- client/weapons/ — weapon data, registry, TacticalWeaponHitscan, WeaponManager
- client/scripts/round_replicator.gd — client-side round state bridge
- server/scripts/round_manager.gd — improved state machine
- server/scripts/plugin_api/plugin_manager.gd — refined plugin system
- config: enemy_tag, ally_tag for meatball targeting

Removed: old C++ SimulationServer GDExtension (replaced by netfox rollback)

addons/netfox.internals/plugin.gd

@@ -0,0 +1,34 @@
+@tool
+extends EditorPlugin
+
+var SETTINGS = [
+	NetfoxLogger._make_setting("netfox/logging/log_level")
+]
+
+func _enter_tree():
+	for setting in SETTINGS:
+		add_setting(setting)
+
+func _exit_tree():
+	if ProjectSettings.get_setting("netfox/general/clear_settings", false):
+		for setting in SETTINGS:
+			remove_setting(setting)
+
+func add_setting(setting: Dictionary):
+	if ProjectSettings.has_setting(setting.name):
+		return
+
+	ProjectSettings.set_setting(setting.name, setting.value)
+	ProjectSettings.set_initial_value(setting.name, setting.value)
+	ProjectSettings.add_property_info({
+		"name": setting.get("name"),
+		"type": setting.get("type"),
+		"hint": setting.get("hint", PROPERTY_HINT_NONE),
+		"hint_string": setting.get("hint_string", "")
+	})
+
+func remove_setting(setting: Dictionary):
+	if not ProjectSettings.has_setting(setting.name):
+		return
+	
+	ProjectSettings.clear(setting.name)