fix: FPS character controller review fixes

- Camera: Make view bob additive to crouch eye height (was overwriting position.y)
- Camera: Sustain sprint FOV kick while sprinting (was recovering immediately)
- Camera: Remove unused _was_sprinting variable
- Controller: Use just_pressed for jump (was sending every frame while held)
- Controller: Direct input dict assignment instead of merge() to avoid alloc
- Controller: Add clearer comments on server-authoritative readback mode

client/characters/character/fps_camera.gd

@@ -70,12 +70,12 @@ var _weapon_rest: Transform3D
 var _base_fov: float = 75.0
 var _current_fov_offset: float = 0.0
 
-## Sway state.
+## Sway state (used as both current value and interpolation target).
 var _sway_current: Vector2 = Vector2.ZERO
 var _sway_target: Vector2 = Vector2.ZERO
 
-## Sprint state cache (detect transition for FOV kick).
-var _was_sprinting: bool = false
+## Base eye Y set by parent controller's crouch logic (for additive bob).
+var _base_eye_y: float = 0.0
 
 # ---------------------------------------------------------------------------
 # Lifecycle
@@ -100,6 +100,10 @@ func _process(delta: float) -> void:
 	if _controller == null:
 		return
 
+	# Capture the eye height set by parent controller's crouch logic
+	# before we apply view bob offsets (which must be additive).
+	_base_eye_y = position.y
+
 	# FOV management
 	_update_fov(delta)
 
@@ -119,16 +123,15 @@ func _process(delta: float) -> void:
 func _update_fov(delta: float) -> void:
 	var target_offset: float = 0.0
 
-	# Sprint FOV kick
-	if _controller.is_sprinting() and not _was_sprinting:
+	# Sprint FOV kick — sustained while sprinting (not just on transition)
+	if _controller.is_sprinting():
 		target_offset = sprint_fov_kick
 
 	# Shoot FOV kick is triggered externally via trigger_shoot_fov()
+	# and decays toward the sprint/walk target naturally via move_toward.
 	_current_fov_offset = move_toward(_current_fov_offset, target_offset, fov_recovery_speed * delta)
 	fov = _base_fov + _current_fov_offset
 
-	_was_sprinting = _controller.is_sprinting()
-
 
 # ---------------------------------------------------------------------------
 # View bobbing
@@ -157,7 +160,9 @@ func _update_bob(delta: float) -> void:
 
 	# Apply bob to camera position (relative to parent's eye offset)
 	position.x = _bob_offset.x
-	position.y = _bob_offset.y
+	# Bob is additive on Y so it does NOT overwrite the crouch eye height
+	# set by the parent FPSCharacterController._update_crouch().
+	position.y = _base_eye_y + _bob_offset.y
 
 
 # ---------------------------------------------------------------------------