Fresh start: replace with naxIO/netfox-cs-sample foundation

Complete replacement of the tactical-shooter project with the
netfox-cs-sample (MIT) — a CS 1.6 inspired multiplayer FPS built
with Godot 4 and netfox.

## What's new
- Full CS-style gameplay: teams (T/CT), rounds, economy, buy menu
- 6 weapons: Knife, Glock, USP, AK-47, M4A1, AWP
- Bomb plant/defuse with 2 bombsites
- Flashbang & smoke grenades
- Proper netfox rollback netcode at 64 tick
- Network popup UI for host/join
- HUD, crosshair, round timer, scoreboard
- All netfox singletons registered as autoloads (works in exported builds)

## Architecture
- Listen-server (host from client, no dedicated server binary)
- Multiplayer-fps game lives at examples/multiplayer-fps/
- Netfox addons registered as autoloads for exported build compat
- Godot 4.7 with Forward+ renderer

## Removed
- Old headless-server architecture (client_main, server_main, player.gd, etc.)
- Custom netfox bootstrap with ENet fallback
- Old ChaffGames FPS template (2,420 lines, 844 KB)
- SimulationServer GDExtension stub
- Godot-jolt physics (netfox sample uses default Godot physics)
- Duplicate weapon_data.gd, anti_cheat.gd, round_manager.gd, etc.
- Server browser API Python venv (87 MB)
- test_range map and modular assets

## Preserved
- Git history
- Server config at config/default_server_config.cfg
- Windows export preset
- Build directory (gitignored)

Co-authored-by: naxIO <naxIO@users.noreply.github.com>

examples/multiplayer-state-machine/scripts/player.gd

@@ -0,0 +1,48 @@
+extends CharacterBody3D
+
+@export var state_machine: RewindableStateMachine
+
+@onready var mesh_instance: MeshInstance3D = $MeshInstance3D
+@onready var current_state_label: Label3D = $StateNameLabel3D
+
+var color: Color:
+	get: return _color
+	set(v): set_color(v)
+
+var _color: Color = Color.WHITE
+var _material: StandardMaterial3D = StandardMaterial3D.new()
+
+# Get the gravity from the project settings to be synced with RigidBody nodes.
+var gravity = ProjectSettings.get_setting(&"physics/3d/default_gravity")
+
+func _ready():
+	# Set spawn position
+	position = Vector3(0, 4, 0)
+	
+	# Set starting state
+	state_machine.state = &"Idle"
+	state_machine.on_display_state_changed.connect(func(_old_state, _new_state):
+		current_state_label.text = state_machine.state
+	)
+	
+	# Ensure material is unique
+	mesh_instance.material_override = _material
+
+# Callback during rollback tick
+func _rollback_tick(delta: float, tick: int, is_fresh: bool) -> void:
+	_force_update_is_on_floor()
+	if not is_on_floor():
+		velocity.y -= gravity * delta
+
+func _force_update_is_on_floor():
+	var old_velocity = velocity
+	velocity = Vector3.ZERO
+	move_and_slide()
+	velocity = old_velocity
+
+func set_color(color: Color):
+	if color == _color:
+		return
+
+	_material.albedo_color = color
+	_color = color