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>

test/snapshot-fixtures.gd

@@ -0,0 +1,52 @@
+extends Object
+class_name SnapshotFixtures
+
+static func state_snapshot(p_position: Vector3 = Vector3.ONE) -> _PropertySnapshot:
+	return _PropertySnapshot.from_dictionary({
+		":position": p_position,
+		":velocity": Vector3.ZERO,
+		":health": 100.
+	})
+
+static func state_properties() -> Array[String]:
+	var result: Array[String] = [
+		":position",
+		":velocity",
+		":health"
+	]
+	return result
+
+static func state_propery_entries(root_node: Node) -> Array[PropertyEntry]:
+	var result: Array[PropertyEntry] = []
+	result.assign(state_properties().map(func(path):
+		return PropertyEntry.parse(root_node, path)
+	))
+	return result
+
+static func state_node() -> StateNode:
+	return StateNode.new()
+
+static func input_snapshot(p_movement: Vector3 = Vector3.ONE) -> _PropertySnapshot:
+	return _PropertySnapshot.from_dictionary({
+		"Input:movement": p_movement,
+		"Input:is_jumping": false
+	})
+
+static func input_property_entries(root_node: Node) -> Array[PropertyEntry]:
+	var result: Array[PropertyEntry] = []
+	result.append(PropertyEntry.parse(root_node, "Input:movement"))
+	result.append(PropertyEntry.parse(root_node, "Input:is_jumping"))
+
+	return result
+
+static func input_node() -> InputNode:
+	var result := InputNode.new()
+	result.name = "Input"
+	return result
+
+class InputNode extends Node:
+	var movement := Vector3.ZERO
+	var is_jumping := false
+
+class StateNode extends Node3D:
+	var health := 100.