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>

.gitignore

@@ -1,12 +1,18 @@
 # Godot
 .godot/
 import/
-*.import
 *.translation
 *.tres~
 *.tscn~
 *.godot
 
+# OS
+.DS_Store
+Thumbs.db
+
+# Build output
+build/
+
 # Editor
 .idea/
 .vscode/
@@ -14,18 +20,17 @@ import/
 *.swo
 *~
 
-# OS
-.DS_Store
-Thumbs.db
+# Python
+__pycache__/
+*.pyc
 
-# Build
-client/build/
-server/build/
-*.zip
-*.exe
-*.pck
+# Netfox
+addons/netfox/encoder/*.gd
+addons/netfox/extras/plugin.cfg
+addons/netfox/icons/*.svg.import
+addons/netfox/internals/plugin.cfg
+addons/netfox/noray/plugin.cfg
+addons/netfox/plugin.cfg
 
-# Secrets (operator must create per deployment)
-server/data/rcon_password.cfg
-build/
-build/
+# Secrets
+rcon_password.cfg