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/forest-brawl/scenes/doodads/cloud-puff-material.tres

@@ -0,0 +1,25 @@
+[gd_resource type="StandardMaterial3D" load_steps=3 format=3 uid="uid://joecqmf51gl0"]
+
+[sub_resource type="Gradient" id="Gradient_t3ujw"]
+interpolation_mode = 2
+colors = PackedColorArray(1, 1, 1, 1, 1, 1, 1, 0)
+
+[sub_resource type="GradientTexture2D" id="GradientTexture2D_6a55y"]
+gradient = SubResource("Gradient_t3ujw")
+width = 256
+height = 256
+fill = 1
+fill_from = Vector2(0.5, 0.5)
+fill_to = Vector2(0.75, 0.5)
+
+[resource]
+transparency = 1
+shading_mode = 2
+specular_mode = 2
+albedo_color = Color(0.701961, 0.901961, 1, 1)
+albedo_texture = SubResource("GradientTexture2D_6a55y")
+rim_tint = 1.0
+texture_repeat = false
+billboard_mode = 1
+billboard_keep_scale = true
+proximity_fade_enabled = true