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>

sh/version.sh

@@ -0,0 +1,46 @@
+#!/bin/bash
+
+# Assume we're running from project root
+source sh/shared.sh
+
+version_major="$(echo ${version} | cut -f1 -d.)"
+version_minor="$(echo ${version} | cut -f2 -d.)"
+version_patch="$(echo ${version} | cut -f3 -d.)"
+version="$version_major.$version_minor.$version_patch"
+
+persist="false"
+
+if (( $# == 0 )); then
+    echo $version
+    exit 0
+fi
+
+if [ $1 == "bump" ]; then
+    if [ "$2" = "major" ]; then
+        version_major=$((version_major + 1));
+        version_minor=0;
+        version_patch=0;
+    elif [ "$2" = "minor" ]; then
+        version_minor=$((version_minor + 1));
+        version_patch=0;
+    elif [ "$2" = "patch" ]; then
+        version_patch=$((version_patch + 1));
+    else
+        >&2 echo "Unknown version part: $2"
+        exit 1
+    fi
+
+    version="$version_major.$version_minor.$version_patch"
+    persist="true"
+elif [ $1 == "envvar" ]; then
+  echo "VERSION=v$version"
+  exit 0
+fi
+
+if [ "$persist" = "true" ]; then
+    for addon in "${addons[@]}"; do
+        sed -i "s/version=.*/version=\"$version\"/g" "addons/$addon/plugin.cfg"
+    done
+fi
+
+echo "$version"