feat: implement WoW macro conditional evaluator for /cast

Adds evaluateMacroConditionals() which parses the [cond1,cond2] Spell;
[cond3] Spell2; Default syntax and returns the first matching
alternative. Supported conditions:

- mod:shift/ctrl/alt, nomod  — keyboard modifier state
- target=player/focus/target, @player/@focus/@target — target override
- help / harm (noharm / nohelp)  — target faction check
- dead / nodead                  — target health check
- exists / noexists              — target presence check
- combat / nocombat              — player combat state
- noform / nostance / form:0     — shapeshift/stance state
- Unknown conditions are permissive (true) to avoid false negatives.

/cast now resolves conditionals before spell lookup and routes
castSpell() to the [target=X] override GUID when specified.
isHostileFaction() exposed as isHostileFactionPublic() for UI use.

include/game/game_handler.hpp

@@ -1888,6 +1888,7 @@ public:
 
     bool isMounted() const { return currentMountDisplayId_ != 0; }
     bool isHostileAttacker(uint64_t guid) const { return hostileAttackers_.count(guid) > 0; }
+    bool isHostileFactionPublic(uint32_t factionTemplateId) const { return isHostileFaction(factionTemplateId); }
     float getServerRunSpeed() const { return serverRunSpeed_; }
     float getServerWalkSpeed() const { return serverWalkSpeed_; }
     float getServerSwimSpeed() const { return serverSwimSpeed_; }