feat(client): add WRONG button F12 bug report capture (#495)

F12 pauses simulation, shows modal LineEdit prompt, saves three files
to user://bug-reports/gauntlet-t{tick}-{timestamp}/: snapshot.json
(full ObserverSnapshot), render.txt (simplified client-side text
render), description.txt (tester notes + tick/room/stance metadata).
Esc cancels without saving. Double-activation guard prevents stacking.

BUG_REPORT action added to InputMapper with wire guard in SimBridge
(client-only, never sent to server). Dialog on ModalLayer (CL 30).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

client/scripts/autoloads/input_mapper.gd

@@ -14,6 +14,7 @@ enum Action {
 	MOVE_SOUTH, MOVE_SOUTHWEST, MOVE_WEST, MOVE_NORTHWEST,
 	INTERACT, USE_PERCEPTION_MODE, OPEN_MENU, PAUSE, UNPAUSE,
 	TOGGLE_STANCE_UP, TOGGLE_STANCE_DOWN,
+	BUG_REPORT,  # #495: F12 WRONG button — client-only, not sent to server
 }
 
 var input_queue: Array[Dictionary] = []
@@ -74,6 +75,8 @@ func _unhandled_input(event: InputEvent) -> void:
 		action = Action.TOGGLE_STANCE_UP
 	elif event.is_action_pressed("stance_down"):
 		action = Action.TOGGLE_STANCE_DOWN
+	elif event.is_action_pressed("bug_report"):
+		action = Action.BUG_REPORT
 
 	if action != -1:
 		input_queue.append({