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/netfox/properties/property-snapshot.test.gd

@@ -0,0 +1,86 @@
+extends VestTest
+
+func get_suite_name() -> String:
+	return "PropertySnapshot"
+
+func test_diff_should_be_empty():
+	# Given
+	var from := _PropertySnapshot.from_dictionary({
+		"foo": 15,
+		"bar": 18,
+	})
+
+	var to := _PropertySnapshot.from_dictionary({
+		"foo": 15,
+		"bar": 18,
+	})
+
+	var expected := _PropertySnapshot.from_dictionary({})
+
+	# When
+	var actual := from.make_patch(to)
+
+	# Then
+	expect_equal(actual.as_dictionary(), expected.as_dictionary())
+
+func test_diff_should_add_unknown():
+	# Given
+	var from := _PropertySnapshot.from_dictionary({
+		"foo": 15,
+	})
+
+	var to := _PropertySnapshot.from_dictionary({
+		"foo": 15,
+		"bar": 18,
+	})
+
+	var expected := _PropertySnapshot.from_dictionary({
+		"bar": 18,
+	})
+
+	# When
+	var actual := from.make_patch(to)
+
+	# Then
+	expect_equal(actual.as_dictionary(), expected.as_dictionary())
+
+func test_diff_should_add_differing():
+	# Given
+	var from := _PropertySnapshot.from_dictionary({
+		"foo": 15,
+		"bar": 18,
+	})
+
+	var to := _PropertySnapshot.from_dictionary({
+		"foo": 35,
+		"bar": 18,
+	})
+
+	var expected := _PropertySnapshot.from_dictionary({
+		"foo": 35
+	})
+
+	# When
+	var actual := from.make_patch(to)
+
+	# Then
+	expect_equal(actual.as_dictionary(), expected.as_dictionary())
+
+func test_diff_should_exclude_removed():
+	# Given
+	var from := _PropertySnapshot.from_dictionary({
+		"foo": 15,
+		"bar": 18,
+	})
+
+	var to := _PropertySnapshot.from_dictionary({
+		"foo": 15,
+	})
+
+	var expected := _PropertySnapshot.from_dictionary({})
+
+	# When
+	var actual := from.make_patch(to)
+
+	# Then
+	expect_equal(actual.as_dictionary(), expected.as_dictionary())