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)

server/server-browser-api/venv/lib/python3.11/site-packages/starlette/exceptions.py

@@ -0,0 +1,43 @@
+from __future__ import annotations
+
+import http
+from collections.abc import Mapping
+
+
+class HTTPException(Exception):
+    def __init__(self, status_code: int, detail: str | None = None, headers: Mapping[str, str] | None = None) -> None:
+        if detail is None:
+            detail = http.HTTPStatus(status_code).phrase
+        self.status_code = status_code
+        self.detail = detail
+        self.headers = headers
+
+    def __str__(self) -> str:
+        return f"{self.status_code}: {self.detail}"
+
+    def __repr__(self) -> str:
+        class_name = self.__class__.__name__
+        return f"{class_name}(status_code={self.status_code!r}, detail={self.detail!r})"
+
+
+class WebSocketException(Exception):
+    def __init__(self, code: int, reason: str | None = None) -> None:
+        self.code = code
+        self.reason = reason or ""
+
+    def __str__(self) -> str:
+        return f"{self.code}: {self.reason}"
+
+    def __repr__(self) -> str:
+        class_name = self.__class__.__name__
+        return f"{class_name}(code={self.code!r}, reason={self.reason!r})"
+
+
+class StarletteDeprecationWarning(UserWarning):
+    """A custom deprecation warning for Starlette.
+
+    Unlike the built-in DeprecationWarning, this inherits from UserWarning to ensure it is visible by default, helping
+    users discover deprecated features without needing to enable warnings explicitly.
+
+    Reference: https://sethmlarson.dev/deprecations-via-warnings-dont-work-for-python-libraries
+    """