Add a new `all` modifier to skills (`strike`, `pierce`, `mortar`, `rally`, `heal`, `enfeeble`, `weaken`, `rupture`) that targets all valid enemies or allies instead of a single target. This includes:
- **Data Layer**: Updated cards.json with expanded skill definitions and added new cards (Imperial Guardian, Pillager, Marauder). Added `allDescription` and `supportsAll` flags to skills.json.
- **Combat Logic**: Extended SkillProcessor and CombatEngine to handle "all" variants, managing parallel state updates for HP, armor, attack stats, and buffs/debuffs across multiple targets.
- **Visuals**: Implemented new animation sequences in BattleScene for area-of-effect skills (parallel projectiles, shared sound effects) and updated CardTooltip/CardObject to display the "all" modifier.
- **Audio**: Introduced a shuffled battle music playlist that cycles through multiple tracks during combat, resuming main menu music upon exit.
Integrate audio feedback across the game by adding new SFX assets and loading them in `BootScene`. Key changes include:
- Added 12 new sound effect files (attacks, abilities, UI) and a main menu music track.
- Implemented SFX playback in `BattleScene` for actions like attacks, counters, mortar/strike/siege/pierce fires, buffs (rally), shields (protect), damage, destructions, and legendary card plays.
- Stopped main menu music during battles to avoid audio overlap and resumed it upon returning to `MainMenuScene`.
- Added hover and select sounds for UI buttons in `MainMenuScene`.
- Fixed deck composition in `DeckManager` by removing one 'imp_trooper_1' from the starter deck.
Brian Fertig