fix(ui): gameplay_occluded signal never fired on first fullscreen toggle

was_occluded was computed AFTER _active_mode and _active_app were
updated to the new values, so it always matched now_occluded on the
first toggle (both TRUE). The signal condition (was != now) never
triggered. Moved the check before the state mutation.

This bug affected every GameplayRenderer (world, entities, fog,
cursor) and the stance indicator — none of them hid on first
fullscreen app open.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

client/scripts/autoloads/hud_groups.gd

@@ -61,6 +61,9 @@ func unregister(node: CanvasItem, group: String) -> void:
 
 ## Open an implant app in fullscreen (default) or insert mode.
 func open_app(app: String, mode: Mode = Mode.FULLSCREEN) -> void:
+	# Capture occlusion state BEFORE mutating — used for change detection below
+	var was_occluded := _active_mode == Mode.FULLSCREEN and not _active_app.is_empty()
+
 	# Close previous app if different
 	if not _active_app.is_empty() and _active_app != app:
 		_set_group_z(_active_app, Z_GAMEPLAY)
@@ -70,7 +73,6 @@ func open_app(app: String, mode: Mode = Mode.FULLSCREEN) -> void:
 	_active_mode = mode
 
 	# Set z-levels based on mode
-	var was_occluded := _active_mode == Mode.FULLSCREEN and not _active_app.is_empty()
 	if mode == Mode.FULLSCREEN:
 		_set_group_z("gameplay", Z_GAMEPLAY)
 		_set_group_z(app, Z_FULLSCREEN)