feat(gauntlet): replace Cleanser with Ghost powerup sticky bypass (v2.4.2)

- Remove entire Cleanser system (signal, vars, HUD, input, RPCs, bot AI)
- Ghost (Invisible Mode) now bypasses sticky tiles in Gauntlet
- Grant Ghost powerup every 2 missions instead of Cleanser charges
- Ghost tiles spawn naturally on Gauntlet arena (15% chance)
- Bots use Ghost powerup when boxed in by sticky tiles
- Players pushed into sticky while Ghost are not slowed
- Remove use_cleanser input action from project.godot
- Remove CleanserHBox UI from gauntlet_hud.tscn
- Bump version to 2.4.2

CHANGELOG_DRAFT.md

@@ -152,7 +152,17 @@
 - Fragment Craft system — collect drops to craft exclusive skins
 - Fixed boot screen stuck on "Checking versions..."
 
-## [2.4.1] — $(date +"%Y-%m-%d")
+## [2.4.2] — 2026-07-03
+- Replaced the **Cleanser** mechanic in Gauntlet mode with a **Ghost powerup** sticky-bypass system.
+- Ghost (Invisible Mode) now lets players walk through sticky candy tiles in Gauntlet — no more hard block.
+- Players earn a Ghost powerup every 2 completed missions in Gauntlet (replaces Cleanser charge grants).
+- Ghost powerup tiles now spawn naturally on the Gauntlet arena (15% chance alongside common tiles).
+- Removed Cleanser HUD elements (icon, label, charge counter) from the Gauntlet overlay.
+- Removed `use_cleanser` input action — Ghost uses the existing powerup activation keybind.
+- Bots now activate Ghost powerup when boxed in by sticky tiles instead of using Cleanser.
+- Players pushed into sticky tiles while in Ghost mode are no longer slowed.
+
+## [2.4.1] — 2026-06-28
 - Fixed Gauntlet map layout to remove red unpassable barrier blocks and center blocks. They are now standard walkable floors but act as hard blockers in physics so players cannot pass them.
 - Fixed Gauntlet mode to prevent powerups or sticky bubbles from spawning on boundary tiles or under the central cannon.
 - Center Candy Cannon now shoots actual projectiles that fly towards sticky cells and leave a VFX trail behind them.