feat(input): full controller support, rebindable controls, and rotation fixes

Playing with a gamepad did not work: all six move_* actions had no joypad
event at all, so a pad could yaw/pitch/roll/turbo but could not translate.
Nothing caught it because every action existed and the game booted fine —
no assertion checked that an action is reachable on *both* devices.

Controller layout, on the 6DOF convention (left stick aims, right stick
translates), using all six of the pad's analog axes for the ship's six
degrees of freedom:

  left stick   yaw + pitch        right stick  strafe + vertical
  LB / RB      roll               RT / LT      forward / back
  L3           turbo              R3           ball camera

Input is now read with Input.get_axis instead of is_action_pressed, so
triggers and sticks are proportional. Keyboard values are unchanged.

Three rotation bugs found by measuring a real Ship rather than reading the
code:

- apply_torque() is world-space and the torque was never rotated into the
  hull's frame (unlike thrust, which uses -ship_basis.z). Roll input became
  pitch after a 90 degree turn and inverted at 180, so the controls were
  correct flying up-field and backwards flying back.
- ship.tscn's inertia is Vector3(7, 1, 7) but a flat torque was applied to
  every axis, giving yaw 7x the angular acceleration of pitch and roll
  (172 deg/s vs 52). Torque is now scaled per-axis by inertia, so
  rotation_acceleration means rad/s^2 and all three axes match. Yaw is
  unchanged.
- pitch_down pitched the nose UP: get_axis's arguments were reversed, so
  the I/K keys and the stick each did the opposite of their label.

Menus were unusable on a pad for a separate reason: Godot 4.7 gives
ui_up/down/left/right joypad events by default but leaves ui_accept and
ui_cancel with none (verified against a pristine project), so a controller
could move the highlight and never press anything. A confirms and B goes
back. Gameplay exits on a new leave_gameplay action (Escape / Start) rather
than ui_cancel, so carrying B for menus cannot abandon a live match.

Bindings for both devices are rebindable in Settings -> Controls, persisted
to user://input.cfg — a separate file from settings.cfg because
VideoSettings.save() rewrites that file wholesale and would drop any
section it does not know about. project.godot stays the source of truth for
defaults; overrides are only ever a delta on top of a boot-time snapshot.

Verified: 268 unit tests, the ENet integration gate, and a 16-sample
before/after comparison of networked prediction residuals showing the
physics change does not regress them (median 0.083m -> 0.065m).

Note for follow-up: every policy in Game/bots/ was trained against the old
sluggish, world-axis rotation and will over-rotate until retrained.

Game/tests/cases/test_project_settings.gd

@@ -71,7 +71,7 @@ func test_physics_engine_is_jolt() -> void:
 func test_required_autoloads_are_registered() -> void:
 	# NetworkManager in particular is reached by name from many scripts; losing
 	# it from [autoload] fails only at the point of use, deep in a smoke test.
-	for autoload_name in ["GameSettings", "ControlPlaneClient", "VideoSettings", "NetworkManager", "MatchNet", "MatchSim"]:
+	for autoload_name in ["GameSettings", "ControlPlaneClient", "VideoSettings", "InputSettings", "NetworkManager", "MatchNet", "MatchSim"]:
 		assert_true(
 			ProjectSettings.has_setting("autoload/" + autoload_name),
 			"autoload/%s registered" % autoload_name
@@ -89,7 +89,12 @@ func test_test_hook_autoloads_are_not_shipped() -> void:
 	# when running those scene-level smoke tests, and must be removed again —
 	# see CLAUDE.md. Shipping one registered would run test code in the real
 	# game, so fail here rather than discovering it in a build.
-	for hook_name in ["MainMenuTestHooks", "LobbyTestHooks", "NetworkedMatchTestHooks"]:
+	# McpInteractionServer is registered automatically by the vendored godot-mcp
+	# tooling whenever it launches the project, and is left behind in
+	# project.godot afterwards. It is a debug channel into a running game, so
+	# shipping it registered is worse than a stray test hook, and it arrives
+	# without anyone having typed it.
+	for hook_name in ["MainMenuTestHooks", "LobbyTestHooks", "NetworkedMatchTestHooks", "McpInteractionServer"]:
 		assert_true(
 			not ProjectSettings.has_setting("autoload/" + hook_name),
 			"test hook autoload/%s must not be registered" % hook_name