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>

addons/netfox/time/network-tickrate-handshake.gd

@@ -40,7 +40,7 @@ signal on_tickrate_mismatch(peer: int, tickrate: int)
 ## [br][br]
 ## Called by [_NetworkTime], no need to call manually.
 func run() -> void:
-	if multiplayer.is_server():
+	if _is_authority():
 		# Broadcast tickrate
 		_submit_tickrate.rpc(NetworkTime.tickrate)
 		
@@ -61,7 +61,7 @@ func _ready() -> void:
 	name = "NetworkTickrateHandshake"
 
 func _handle_new_peer(peer: int) -> void:
-	if multiplayer.is_server():
+	if _is_authority():
 		_submit_tickrate.rpc_id(peer, NetworkTime.tickrate)
 
 func _handle_tickrate_mismatch(peer: int, tickrate: int) -> void:
@@ -74,21 +74,25 @@ func _handle_tickrate_mismatch(peer: int, tickrate: int) -> void:
 					NetworkTime.tickrate, peer, tickrate
 				])
 		DISCONNECT:
-			if multiplayer.is_server():
+			if _is_authority():
 				_logger.warning("Peer #%d's tickrate of %dtps differs from expected %dtps! Disconnecting.", [
 					peer, tickrate, NetworkTime.tickrate
 				])
 				multiplayer.multiplayer_peer.disconnect_peer(peer)
 		ADJUST:
-			if not multiplayer.is_server():
+			if not _is_authority():
 				_logger.info("Local tickrate %dtps differs from tickrate of host at %dtps! Adjusting.", [
 					NetworkTime.tickrate, tickrate
 				])
 				# TODO: Make tickrate mutable at user's digression
-				ProjectSettings.set_setting(&"netfox/time/tickrate", tickrate)
+				NetworkTime._tickrate = tickrate
 		SIGNAL:
 			on_tickrate_mismatch.emit(peer, tickrate)
 
+func _is_authority() -> bool:
+	# HACK: This method is here to ease testing; pretending to be a client is messy from a unit test
+	return multiplayer.is_server()
+
 @rpc("any_peer", "reliable", "call_remote")
 func _submit_tickrate(tickrate: int) -> void:
 	var sender := multiplayer.get_remote_sender_id()