Major gameplay improvements - barriers, HP regen, descent mechanic

- 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

worklog.md

@@ -610,3 +610,57 @@ Stage Summary:
 - Transference mana type verified and working
 - Crafting slice TODOs resolved with proper skill integration
 - All lint checks pass
+
+---
+Task ID: 20
+Agent: Main
+Task: Major gameplay improvements - barriers, HP regen, descent mechanic, skill cleanup
+
+Work Log:
+- **Fixed transference mana display**:
+  - Updated ManaDisplay to show unlocked elements even with 0 mana
+  - Previously filtered to elements with current >= 1
+
+- **Removed blocking/dodging mechanics** (player has no health):
+  - Replaced Seer's `foresight` (dodge) with `criticalMastery` (crit damage)
+  - Replaced Warden's defensive skills with mana efficiency skills
+  - Replaced Strider's `evasive` (dodge) with `fluidMotion` (combo duration)
+  - Warden now focuses on mana efficiency and resource management
+
+- **Added guardian barriers**:
+  - Added `barrier` property to GuardianDef in types.ts
+  - Added barriers to all 10 guardians (50% of HP)
+  - Barriers are extra HP that must be depleted before main HP
+  - Barriers do NOT regenerate (one-time shield)
+  - UI shows gray barrier bar above main HP when active
+
+- **Added floor HP regeneration**:
+  - Created `getFloorHPRegen()` function - scales with floor level
+  - Non-guardian floors regen 1% + 0.2% per floor HP per hour
+  - Guardian floors have 0 regen
+  - Regen only happens during combat (climbing action)
+
+- **Implemented climb-down mechanic**:
+  - Added `climbDirection` ('up' | 'down') and `isDescending` to GameState
+  - Added `floorBarrier` and `floorMaxBarrier` to GameState
+  - Created `exitSpire()` function that triggers descent
+  - When descending, player must fight through each floor to floor 1
+  - Cannot switch away from climb while above floor 1 - must descend first
+  - On guardian defeat during descent, no pact is signed
+  - Updated UI with descent indicator and exit spire button
+
+- **Updated SpireTab UI**:
+  - Shows barrier bar for guardian floors
+  - HP bar grays out when barrier is active
+  - Added "Exit Spire" button during climb
+  - Shows descent status indicator
+
+- **Updated store persistence**:
+  - Added new fields to partialize function for save/load
+
+Stage Summary:
+- Guardian barriers add strategic depth - must break shield before damaging
+- Floor HP regen makes higher floors harder without burst DPS
+- Descent mechanic ensures player must survive entire climb in one go
+- Blocking/dodging skills replaced with meaningful alternatives
+- All lint checks pass