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/nodes/state-synchronizer.md

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+# StateSynchronizer
+
+Synchronizes state from the node's authority to other peers.
+
+Similar to Godot's [MultiplayerSynchronizer], but is tied to the [network tick
+loop]. Works well with [TickInterpolator].
+
+One way to use this node is to synchronize logic that runs only on the server,
+for example NPC's in your games. The NPC's are controlled fully by the server,
+and their state is synchronized to the clients by the *StateSynchronizer*
+nodes.
+
+## Configuring state
+
+To use *StateSynchronizer*, add it as a child to the target node, specify the
+root node, and configure which properties to synchronize:
+
+![StateSynchronizer configuration](../assets/state-synchronizer-config.png)
+
+*Root* specifies the root node for resolving properties. Best practice dictates
+to add *StateSynchronizer* under its target, so *Root* will most often be the
+*StateSynchronizer*'s parent node.
+
+*Properties* are recorded for each tick on the node's authority ( usually the
+server ), and broadcast to other peers. These are analogous to
+[RollbackSynchronizer]'s *state properties*.
+
+See [Property paths] on how to specify properties.
+
+## Changing configuration
+
+*StateSynchronizer* has to do some setup work whenever the state or the
+input properties change.
+
+By default, this work is done upon instantiation. If you need to change
+properties during runtime, make sure to call `process_settings()`, otherwise
+*StateSynchronizer* won't apply the changes.
+
+You can change the node's authority without calling `process_settings()` again.
+Make sure that the authority is changed the same way on all peers, to avoid
+discrepancies.
+
+## When to use StateSynchronizer and MultiplayerSynchronizer
+
+Part of the design philosophy of netfox is to build *on top of* Godot's
+networking tools, instead of *replacing* them.
+
+Both [MultiplayerSynchronizer] and StateSynchronizer can be used to synchronize
+state from authority to the rest of the peers.
+
+[MultiplayerSynchronizer] uses its own timer, and is independent of netfox's
+[network tick loop]. It can also do delta updates, and manage visibility per
+peer. Since it is not tied to netfox's tick loop, it does not work with
+[TickInterpolator].
+
+StateSynchronizer records all the properties specified and broadcasts them
+as-is to all peers. This does not include visiblity or delta updates. The
+broadcast happens on every network tick. This node is explicitly designed to
+work with [TickInterpolator].
+
+---
+
+You can use StateSynchronizer for properties that you want to be interpolated,
+like position, rotation, or any other visual properties.
+
+You can use [MultiplayerSynchronizer] for properties that either don't need
+interpolation ( e.g. a unit's HP ), or specifically need one of
+[MultiplayerSynchronizer]'s features.
+
+[MultiplayerSynchronizer]: https://docs.godotengine.org/en/stable/classes/class_multiplayersynchronizer.html
+[network tick loop]: ../guides/network-time.md
+[TickInterpolator]: ./tick-interpolator.md
+[RollbackSynchronizer]: ./rollback-synchronizer.md
+[Property paths]: ../guides/property-paths.md