various: add speed/cooldown & initiative system

- Goblins act every ~2 turns, skeletons ~1.5, orcs ~1.2
- Enemies accumulate cooldown based on speed, act when <= 0
- Player always acts every turn (speed = 100)"

Signed-off-by: NotAShelf <raf@notashelf.dev>
Change-Id: Id822579a0326887d91a80bd4ab27a72d6a6a6964

src/enemy.h

@@ -9,6 +9,9 @@ void enemy_spawn(Enemy enemies[], int *count, Map *map, Player *p, int floor);
 // Update all enemy AI
 void enemy_update_all(Enemy enemies[], int count, Player *p, Map *map);
 
+// Perform a single action for an enemy (attack if adjacent, otherwise move)
+void enemy_act(Enemy *e, Player *p, Map *map, Enemy *all_enemies, int enemy_count);
+
 // Check if position has an enemy
 int is_enemy_at(const Enemy *enemies, int count, int x, int y);