debug: add GO interaction diagnostics at every decision point

Adds [GO-DIAG] WARNING-level logs at:
- Right-click dispatch (raypick hit / re-interact with target)
- interactWithGameObject entry + all BLOCKED paths
- SMSG_SPELL_GO (wasInTimedCast, lastGoGuid, pendingGoGuid state)
- SMSG_LOOT_RESPONSE (items, gold, guid)
- Raypick candidate GO positions (entity pos + hit center + radius)

These logs will pinpoint exactly where the interaction fails:
- No GO-DIAG lines = GOs not in entity manager / not visible
- Raypick GO pos=(0,0,0) = GO position not set from update block
- BLOCKED = guard condition preventing interaction
- SPELL_GO wasInTimedCast=false = timer race (already fixed)

src/game/game_handler.cpp

@@ -6114,10 +6114,14 @@ void GameHandler::interactWithNpc(uint64_t guid) {
 }
 
 void GameHandler::interactWithGameObject(uint64_t guid) {
-    if (guid == 0) return;
-    if (!isInWorld()) return;
+    LOG_WARNING("[GO-DIAG] interactWithGameObject called: guid=0x", std::hex, guid, std::dec);
+    if (guid == 0) { LOG_WARNING("[GO-DIAG] BLOCKED: guid==0"); return; }
+    if (!isInWorld()) { LOG_WARNING("[GO-DIAG] BLOCKED: not in world"); return; }
     // Do not overlap an actual spell cast.
-    if (spellHandler_ && spellHandler_->casting_ && spellHandler_->currentCastSpellId_ != 0) return;
+    if (spellHandler_ && spellHandler_->casting_ && spellHandler_->currentCastSpellId_ != 0) {
+        LOG_WARNING("[GO-DIAG] BLOCKED: already casting spellId=", spellHandler_->currentCastSpellId_);
+        return;
+    }
     // Always clear melee intent before GO interactions.
     stopAutoAttack();
     // Set the pending GO guid so that: