handle giveKeyChainTriggeredMessage with ChainStage = 0

src/services/questService.ts

@@ -83,6 +83,7 @@ export const updateQuestStage = (
             `Quest stage index mismatch: stage is ${ChainStage} but array size is ${quest.Progress.length}`
         );
     }
+    // Note that the client may use index 0 as well, e.g. for rising tide's initial inbox message. 'm' is not tracked for it.
     if (ChainStage >= 0) {
         const questStage = quest.Progress[ChainStage]; // guaranteed in-bounds now