refactor: Replace natural-regen disciplines with mana conversion speed disciplines

- Add conversionRate + sourceManaTypes fields to DisciplineDefinition
- Rewrite elemental-regen.ts: 8 base disciplines now convert raw→element
- Rewrite elemental-regen-advanced.ts: 6 composite/exotic disciplines with proper source recipes
- Update discipline-effects.ts: produce conversion entries instead of regen bonuses
- Update gameStore.ts tick: drain source mana types, add to target element
- Update discipline-slice.ts: gate activation on source mana type access
- Update discipline-math.ts: resolve mana type IDs to 'X mana' display names
- Update DisciplinesTab.tsx: show conversion info, source requirements, and lock state
- Update DisciplineDebugSection.tsx: pass elements to activate()
- Update effects.ts: remove regen_{element} merge (no longer produced)

src/lib/game/effects.ts

@@ -93,14 +93,10 @@ export function computeAllEffects(
     }
   }
 
-  // Merge per-element regen from discipline effects (regen_{element})
+  // Per-element regen from discipline effects (regen_{element}) — no longer produced
+  // by elemental disciplines (they now use conversion instead).
+  // Kept for backward compatibility with any upgrade effects that may provide per-element regen.
   const perElementRegenBonus: Record<string, number> = { ...upgradeEffects.perElementRegenBonus };
-  for (const [key, value] of Object.entries(disciplineEffects.bonuses)) {
-    if (key.startsWith('regen_') && key !== 'regenBonus') {
-      const element = key.replace('regen_', '');
-      perElementRegenBonus[element] = (perElementRegenBonus[element] || 0) + value;
-    }
-  }
 
   // Merge per-element cap bonuses from discipline effects (elementCap_{element})
   for (const [key, value] of Object.entries(disciplineEffects.bonuses)) {