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/tutorials/interpolation-caveats.md

@@ -0,0 +1,39 @@
+# Interpolation caveats
+
+While netfox runs netcode at a fixed rate, the game may render frames at a
+higher, varying framerate. Interpolation smooths out the difference between
+tickrate and framerate, when using [TickInterpolator].
+
+Below are some aspects that may catch users off guard.
+
+### Interpolate only visuals
+
+A node's state may consist of multiple properties, some of which affect its
+appearance ( e.g. position, rotation, scale ), some are only relevant to the
+simulation - e.g. most objects look the same regardless of their velocity, even
+though it's important for simulating their behavior.
+
+Since interpolation matters only for the game's visuals, it's enough to
+interpolate only the properties that affect the game's visuals.
+
+### Rotation vs. Quaternion vs. Transform
+
+Interpolating `rotation` may lead to glitchy results when an object makes a
+full turn. This stems from the way `rotation` works - it represents the amount
+of rotation per axis, in Euler angles. Using Euler angles to interpolate
+rotations doesn't work well, as they can end up interpolating from -180 degrees
+to +180 numerically. The expected behavior would be to go from -180 to +180
+instantly, since they represent the same rotation. The same thing happens in
+animation software as well, when trying to interpolate with Euler angles.
+
+What to do instead:
+
+* Interpolate the whole `transform`
+* Interpolate `quaternion` - represents rotation, but better suited to
+  interpolation
+
+For more, see Godot docs on [3D transforms]
+
+[TickInterpolator]: ../nodes/tick-interpolator.md
+[3D transforms]: https://docs.godotengine.org/en/stable/tutorials/3d/using_transforms.html
+