Phase 7: netfox + godot-jolt stack upgrade

Stack installed:
- netfox v1.35.3 (core + extras + noray + internals)
- godot-jolt v0.16.0-stable

Architecture:
- Server: ENet transport (works headless, no netfox deps)
- Client/Editor: netfox rollback (RollbackSynchronizer, TickInterpolator)

New/modified:
- docs/migration-netfox-plan.md — migration architecture
- scripts/network/network_manager.gd — netfox-aware ENet fallback
- scripts/network/player.gd — clean base player
- client/characters/player_netfox.gd — rollback player w/ WeaponManager
- client/characters/input/player_net_input.gd — BaseNetInput subclass
- client/characters/character/fps_character_controller.gd — netfox input feed
- client/weapons/ — weapon data, registry, TacticalWeaponHitscan, WeaponManager
- client/scripts/round_replicator.gd — client-side round state bridge
- server/scripts/round_manager.gd — improved state machine
- server/scripts/plugin_api/plugin_manager.gd — refined plugin system
- config: enemy_tag, ally_tag for meatball targeting

Removed: old C++ SimulationServer GDExtension (replaced by netfox rollback)

addons/godot-jolt/godot-jolt.gdextension

@@ -0,0 +1,41 @@
+[godot-jolt]
+version = "0.16.0-stable"
+build = "8eca5bb795"
+
+[configuration]
+
+entry_symbol = "godot_jolt_main"
+compatibility_minimum = "4.3"
+compatibility_maximum = "4.7"
+
+[libraries]
+
+windows.release.single.x86_64 = "windows/godot-jolt_windows-x64.dll"
+windows.debug.single.x86_64 = "windows/godot-jolt_windows-x64_editor.dll"
+
+windows.release.single.x86_32 = "windows/godot-jolt_windows-x86.dll"
+windows.debug.single.x86_32 = "windows/godot-jolt_windows-x86_editor.dll"
+
+linux.release.single.x86_64 = "linux/godot-jolt_linux-x64.so"
+linux.debug.single.x86_64 = "linux/godot-jolt_linux-x64_editor.so"
+
+linux.release.single.x86_32 = "linux/godot-jolt_linux-x86.so"
+linux.debug.single.x86_32 = "linux/godot-jolt_linux-x86_editor.so"
+
+macos.release.single = "macos/godot-jolt_macos.framework"
+macos.debug.single = "macos/godot-jolt_macos_editor.framework"
+
+ios.release.single = "ios/godot-jolt_ios.framework"
+ios.debug.single = "ios/godot-jolt_ios_editor.framework"
+
+android.release.single.arm64 = "android/libgodot-jolt_android-arm64.so"
+android.debug.single.arm64 = "android/libgodot-jolt_android-arm64_editor.so"
+
+android.release.single.arm32 = "android/libgodot-jolt_android-arm32.so"
+android.debug.single.arm32 = "android/libgodot-jolt_android-arm32_editor.so"
+
+android.release.single.x86_64 = "android/libgodot-jolt_android-x64.so"
+android.debug.single.x86_64 = "android/libgodot-jolt_android-x64_editor.so"
+
+android.release.single.x86_32 = "android/libgodot-jolt_android-x86.so"
+android.debug.single.x86_32 = "android/libgodot-jolt_android-x86_editor.so"