Quaternius weapons, input fixes, sound & path fixes

- Added 6 Quaternius weapon models (Pistol, Revolver, Rifle, Shotgun, P90, SniperRifle)
- Created weapon resource files with balanced stats
- Wired Pistol + Rifle into player.tscn replacing Kenney blasters
- Fixed WASD input (matched input map action names)
- Fixed Escape key toggles mouse capture
- Added Audio autoload singleton
- Fixed broken sound asset paths across all scripts
- Fixed all scene ext_resource text paths (nested under assets/kenney-fps/)
- Fixed all .import source_file paths
- Deleted stale .import files (will be regenerated by editor on open)

project.godot

@@ -41,6 +41,7 @@ NetworkSynchronizationServer="*res://addons/netfox/servers/network-synchronizati
 NetworkIdentityServer="*res://addons/netfox/servers/network-identity-server.gd"
 NetworkCommandServer="*res://addons/netfox/servers/network-command-server.gd"
 WeaponRegistry="*res://examples/multiplayer-fps/scripts/data/weapon_registry.gd"
+Audio="*res://assets/kenney-fps/scripts/audio.gd"
 
 [display]
 
@@ -55,7 +56,7 @@ enabled=PackedStringArray("res://addons/netfox.extras/plugin.cfg", "res://addons
 [filesystem]
 
 import/blender/enabled=false
-import/fbx/enabled=false
+import/fbx/enabled=true
 
 [input]