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/setuptools/_reqs.py

@@ -0,0 +1,42 @@
+from __future__ import annotations
+
+from collections.abc import Iterable, Iterator
+from functools import lru_cache
+from typing import TYPE_CHECKING, Callable, TypeVar, Union, overload
+
+import jaraco.text as text
+from packaging.requirements import Requirement
+
+if TYPE_CHECKING:
+    from typing_extensions import TypeAlias
+
+_T = TypeVar("_T")
+_StrOrIter: TypeAlias = Union[str, Iterable[str]]
+
+
+parse_req: Callable[[str], Requirement] = lru_cache()(Requirement)
+# Setuptools parses the same requirement many times
+# (e.g. first for validation than for normalisation),
+# so it might be worth to cache.
+
+
+def parse_strings(strs: _StrOrIter) -> Iterator[str]:
+    """
+    Yield requirement strings for each specification in `strs`.
+
+    `strs` must be a string, or a (possibly-nested) iterable thereof.
+    """
+    return text.join_continuation(map(text.drop_comment, text.yield_lines(strs)))
+
+
+# These overloads are only needed because of a mypy false-positive, pyright gets it right
+# https://github.com/python/mypy/issues/3737
+@overload
+def parse(strs: _StrOrIter) -> Iterator[Requirement]: ...
+@overload
+def parse(strs: _StrOrIter, parser: Callable[[str], _T]) -> Iterator[_T]: ...
+def parse(strs: _StrOrIter, parser: Callable[[str], _T] = parse_req) -> Iterator[_T]:  # type: ignore[assignment]
+    """
+    Replacement for ``pkg_resources.parse_requirements`` that uses ``packaging``.
+    """
+    return map(parser, parse_strings(strs))