feat(ui): add in-game debug console with tilde toggle and command dispatch (#581)
- debug_console.gd: new ModalLayer Control — tilde key toggles bottom-40% panel,
command history (up/down), SimBridge dispatch for all DebugCommandKind variants:
ticks, contaminate, tp, activate, triangle, npc, triangles, pop, status, help
- debug_console.tscn: minimal scene node; UI built programmatically in _ready()
- input_mapper.gd: DEBUG_COMMAND action added to Action enum
- sim_bridge.gd: DEBUG_COMMAND → "DebugCommand" wire mapping
- protocol.gd: v18 debug_response decode (command, text, success fields)
- game_state.gd: debug_response field + apply_snapshot one-shot handling
- main.gd: @onready ref, router registration, _consume_debug_response(), settings signal
- settings_dialog.gd: debug_console_toggled signal + CheckButton toggle row (+36px height),
reads initial state from user://settings.cfg; CheckButton state loaded from PREFS_PATH
- main.tscn: DebugConsole node on ModalLayer, load_steps 27→28
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>