refactor: remove skill system leftovers, migrate click mana to discipline perk

- Simplified getMeditationBonus() to continuous ramp formula
- Added click-mana capped perk to Mana Circulation discipline
- Removed manaWell/manaFlow/manaSpring skill reads and prestige upgrades
- Removed all skill fields from GameState and GameActionType
- Updated all call sites and tests (916 tests passing)

Closes #174

src/lib/game/stores/manaStore.ts

@@ -45,9 +45,6 @@ export interface ManaActions {
   // Reset
   resetMana: (
     prestigeUpgrades: Record<string, number>,
-    skills?: Record<string, number>,
-    skillUpgrades?: Record<string, string[]>,
-    skillTiers?: Record<string, number>
   ) => void;
 }
 
@@ -193,9 +190,6 @@ export const useManaStore = create<ManaStore>()(
 
       resetMana: (
         prestigeUpgrades: Record<string, number>,
-        _skills: Record<string, number> = {},
-        _skillUpgrades: Record<string, string[]> = {},
-        _skillTiers: Record<string, number> = {}
       ) => {
         const elementMax = 10 + (prestigeUpgrades.elemMax || 0) * 5;
         const startingMana = 10 + (prestigeUpgrades.manaStart || 0) * 10;