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/multiplayer-fps/attribution.md

@@ -0,0 +1,50 @@
+# Attributions
+
+This document outlines the sources of the sound effects and textures used.
+Thank you all for the freely usable resources!
+
+## Bullethole
+
+[Source](https://opengameart.org/content/bullet-decal-bullethole0png)
+
+Appears when a bullet hits a wall.
+
+Files:
+
+* `textures/bullet_hole.png`
+
+*"Bullet Decal Bullethole"* by [musdasch], under the [Creative Commons 0]
+license.
+
+## Crosshair
+
+Created by krazyjakee (PR author).
+
+Files:
+
+* `textures/crosshair.png`
+
+*"Crosshair"* by [krazyjakee], under the [Creative Commons 0] license.
+
+## Sound Effects
+
+[Source](https://sonniss.com/category/sound-libraries)
+
+Weapons and damage sound effects
+
+Files:
+
+* `sounds/death.wav`
+* `sounds/fire.mp3`
+* `sounds/hit.wav`
+
+*"GameAudioGDC Bundle"* by [sonniss](https://sonniss.com/), under the
+[Unlimited User License] license.
+
+
+[musdasch]: https://opengameart.org/users/musdasch
+[krazyjakee]: https://github.com/krazyjakee
+[sonniss]: https://sonniss.com/
+
+[Creative Commons 0]: https://creativecommons.org/publicdomain/zero/1.0/
+[Unlimited User License]: https://sonniss.com/gdc-bundle-license