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/single-player/scripts/player.gd

@@ -0,0 +1,24 @@
+extends CharacterBody3D
+
+@export var speed = 5.0
+
+# Get the gravity from the project settings to be synced with RigidBody nodes.
+var gravity = ProjectSettings.get_setting(&"physics/3d/default_gravity")
+
+func _physics_process(delta):
+	# Add the gravity.
+	if not is_on_floor():
+		velocity.y -= gravity * delta
+
+	# Get the input direction and handle the movement/deceleration.
+	# As good practice, you should replace UI actions with custom gameplay actions.
+	var input_dir = Input.get_vector("ui_left", "ui_right", "ui_up", "ui_down")
+	var direction = (transform.basis * Vector3(input_dir.x, 0, input_dir.y)).normalized()
+	if direction:
+		velocity.x = direction.x * speed
+		velocity.z = direction.z * speed
+	else:
+		velocity.x = move_toward(velocity.x, 0, speed)
+		velocity.z = move_toward(velocity.z, 0, speed)
+
+	move_and_slide()