Refactor pack system to faction-specific packs with slot-based drops
- Split standard pack into 5 faction-specific packs (imperial, raider, bloodthirsty, xeno, righteous)
- Each pack has 3 guaranteed common slots + 1 special slot with tiered rarity distribution
- Packs unlock by completing their respective campaign missions
- Updated StoreScene to display faction colors, unlock status, and support pack opening animations
Fix bloodpact skill trigger timing and mechanics
- Changed bloodpact from preBattle to preAttack trigger (now fires per attack instead of once per turn)
- Reduced HP cost to 50% of value (was 100%), maintaining same ATK gain
- Moved bloodpact processing from _collectPreBattleFires to _buildPendingAttacks
- Added death check for self-killed cards during preAttack phase
Update drain skill description and trigger
- Changed drain from preBattle to preAttack trigger
- Updated description to clarify it targets the opposing card and its neighbors
Add fusion activation video and enhanced reveal effects
- Added forge2.mp4 for fusion animation (swaps with idle forge during activation)
- Implemented 3-phase energy vortex effect: particle streams, lightning bolts, convergence flash
- Faction-colored effects based on selected stack's faction
Update attack spritesheet and card data
- Updated attacks.png/psd with new bloodpact visual (frame 24)
- Changed all bloodpact skill triggers in cards.json from preBattle to preAttack
```