feat: implement golemancy combat system (spec §6, §9)

- Add ActiveGolem interface and activeGolems to GolemancyState
- Add maxRoomDuration to all 12 golem definitions
- Create golem-combat-actions.ts with pure golem combat logic (summoning, maintenance, attacks, room-duration)
- Create golem-combat.ts pipeline for golem combat setup
- Wire golem maintenance and attacks into processCombatTick
- Wire golem summoning into advanceRoomOrFloor on room entry
- Wire golem room-duration countdown into onFloorCleared callback
- Update combat-actions tests for new processCombatTick signature
- All 921 tests pass, all files under 400-line limit

Closes #259

src/lib/game/__tests__/combat-actions.test.ts

@@ -36,7 +36,7 @@ function resetStores() {
     roomResetState: {},
     clearedRooms: {},
     isDescentComplete: false,
-    golemancy: { enabledGolems: [], summonedGolems: [], lastSummonFloor: 0 },
+    golemancy: { enabledGolems: [], summonedGolems: [], activeGolems: [], lastSummonFloor: 0 },
     equipmentSpellStates: [],
     comboHitCount: 0,
     floorHitCount: 0,
@@ -56,6 +56,12 @@ function resetStores() {
   useDisciplineStore.setState({ disciplines: {}, activeIds: [], concurrentLimit: 1, totalXP: 0, processedPerks: [] });
 }
 
+function golemApplyDamageToRoom(dmg: number): { floorHP: number; floorMaxHP: number; roomCleared: boolean } {
+  const cs = useCombatStore.getState();
+  const newFloorHP = Math.max(0, cs.floorHP - dmg);
+  return { floorHP: newFloorHP, floorMaxHP: cs.floorMaxHP, roomCleared: newFloorHP <= 0 };
+}
+
 function runCombatTick(rawMana: number, elements: Record<string, { current: number; max: number; unlocked: boolean }>): CombatTickResult {
   return processCombatTick(
     () => useCombatStore.getState(),
@@ -67,6 +73,27 @@ function runCombatTick(rawMana: number, elements: Record<string, { current: numb
     vi.fn(), // onFloorCleared
     (dmg) => ({ rawMana, elements, modifiedDamage: dmg }), // onDamageDealt (no modifiers)
     [],   // signedPacts
+    { activeGolems: [] }, // golemancyState
+    golemApplyDamageToRoom,
+  );
+}
+
+function processCombatTickDirect(
+  get: () => ReturnType<typeof useCombatStore.getState>,
+  set: (partial: Record<string, unknown>) => void,
+  rawMana: number,
+  elements: Record<string, { current: number; max: number; unlocked: boolean }>,
+  maxMana: number,
+  attackSpeedMult: number,
+  onFloorCleared: (floor: number, wasGuardian: boolean) => void,
+  onDamageDealt: (dmg: number) => { rawMana: number; elements: Record<string, { current: number; max: number; unlocked: boolean }>; modifiedDamage?: number },
+  signedPacts: number[],
+): CombatTickResult {
+  return processCombatTick(
+    get, set, rawMana, elements, maxMana, attackSpeedMult,
+    onFloorCleared, onDamageDealt, signedPacts,
+    { activeGolems: [] },
+    golemApplyDamageToRoom,
   );
 }
 
@@ -160,7 +187,7 @@ describe('processCombatTick', () => {
       const elements = makeInitialElements(500, {});
       const state = useCombatStore.getState();
       // With 0 mana and 0 progress, no cast should complete
-      const result = processCombatTick(
+      const result = processCombatTickDirect(
         () => state,
         () => {},
         0, // no mana
@@ -196,7 +223,7 @@ describe('processCombatTick', () => {
       // path that acts as a safety net.
       useCombatStore.setState({ activeSpell: 'totallyInvalidSpell' });
       const elements = makeInitialElements(500, {});
-      const result = processCombatTick(
+      const result = processCombatTickDirect(
         () => useCombatStore.getState(),
         () => {},
         1000,
@@ -218,7 +245,7 @@ describe('processCombatTick', () => {
       const elements = makeInitialElements(500, {});
       useCombatStore.setState({ castProgress: 0.99 });
       expect(() => {
-        processCombatTick(
+        processCombatTickDirect(
           () => useCombatStore.getState(),
           () => {},
           1000,