- Fix transference mana display (show unlocked elements even with 0 mana)
- Remove blocking/dodging mechanics (player has no health):
- Replace Seer's foresight with criticalMastery
- Replace Warden's defensive skills with mana efficiency skills
- Replace Strider's evasive with fluidMotion
- Add guardian barriers (50% of HP, doesn't regenerate)
- Add floor HP regeneration (scales with floor level, 0 for guardians)
- Implement climb-down mechanic:
- Cannot switch away from climb while above floor 1
- Must fight through each floor to exit
- Exit Spire button triggers descent
- Update UI to show barrier bar and descent status
