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>

docs/netfox/guides/interpolators.md

@@ -0,0 +1,100 @@
+# Interpolators
+
+Tracks interpolators for various data types. Provided as a static class.
+
+To smooth out motion between network ticks, [TickInterpolator] interpolates
+nodes' state properties between the current and the previous tick. The type of
+data to be interpolated is not known in advance, and can be any built-in or
+even custom type configured by the developer.
+
+*Interpolators* provides methods to register interpolators for any data type,
+and even provides some for built-in data types.
+
+## Interpolating values
+
+*Interpolators* can be used to interpolate between any two values, as long as
+they hold the same data type:
+
+```gdscript
+extends Node3D
+
+@export var target_node
+@export var approach_time = 0.5
+
+func _process(delta):
+  # Approach target node, if it exists
+  if target_node:
+    var from_xform = global_transform
+    var to_xform = target_node.global_transform
+    var factor = delta / approach_time
+
+    global_transform = Interpolators.interpolate(from_xform, to_xform, factor)
+```
+
+Note that in this case, *Interpolators* will try to look up the appropriate
+interpolator based on the provided values. If no interpolator is found, a
+fallback is used, that simply returns the value closer to *factor* - i.e. the
+starting value if *factor* is less than 0.5 and the target value otherwise.
+
+## Caching interpolators
+
+To avoid having to look up the right interpolator every frame, you can cache
+it:
+
+```gdscript
+extends Node3D
+
+@export target_node
+@export approach_time = 0.5
+
+var interpolator
+
+func _ready():
+  interpolator = Interpolators.find_for(global_transform)
+
+func _process(delta):
+  # Approach target node, if it exists
+  if target_node:
+    var from_xform = global_transform
+    var to_xform = target_node.global_transform
+    var factor = delta / approach_time
+
+    global_transform = interpolator.call(from_xform, to_xform, factor)
+```
+
+## Custom interpolators
+
+*Interpolators* supports interpolators for custom data types, and even
+overriding built-in interpolators. Both can be done by registering an
+interpolator:
+
+```gdscript
+Interpolators.register(
+  func(a): return a is float,               # Condition
+  func(a, b, f): return lerpf(a, b, f * f)  # Interpolation
+)
+```
+
+The above registers a custom interpolator by specifying a condition function
+and an interpolation function. Since it applies to an already supported type,
+it overrides the built-in interpolator.
+
+During lookup, *Interpolators* calls the *condition* function of each
+interpolator and returns the one whose *condition* function returns true. If
+multiple interpolators are applicable, *Interpolators* returns the last
+registered one.
+
+The *interpolation* function receives the starting value *a*, the target value
+*b* and the interpolation factor *f*.
+
+## Built-in interpolators
+
+The following types are supported by default:
+
+* float
+* Vector2
+* Vector3
+* Transform2D
+* Transform3D
+
+[TickInterpolator]: ../nodes/tick-interpolator.md