Fix BUG 2: Set currentAction to 'study' when starting skill or spell study

The startStudyingSkill() and startStudyingSpell() functions in skillStore.ts
were setting currentStudyTarget but not updating currentAction in combatStore.
Added useCombatStore.getState().setAction('study') calls to both functions
so the game tick properly processes study progress.

src/lib/game/stores/combatStore.ts

@@ -77,6 +77,8 @@ export interface CombatState {
   setIsDescending: (descending: boolean) => void;
   climbDownFloor: () => void;
   exitSpireMode: () => void;
+  startClimbUp: () => void;
+  startClimbDown: () => void;
   
   // Golemancy
   toggleGolem: (golemId: string) => void;
@@ -254,6 +256,10 @@ export const useCombatStore = create<CombatState>()(
         set({ spireMode: false, climbDirection: null, isDescending: false });
       },
       
+      startClimbUp: () => set({ climbDirection: 'up', currentAction: 'climb' }),
+      
+      startClimbDown: () => set({ climbDirection: 'down', currentAction: 'climb' }),
+      
       // Golemancy
       toggleGolem: (golemId: string) => {
         set((s) => {