feat: WorldState memory, increased context, better error handling

- Added WorldState types for character location tracking
- Increased RECENT_MESSAGES_COUNT from 6 to 15
- Increased server limits (50k/200k chars)
- Added language reminders to system prompts
- Better error logging for 400 errors

src/pages/GamePage.tsx

@@ -9,6 +9,8 @@ import {
   sendMessage,
   generateStorySummary,
   extractKeyEvents,
+  updateWorldState,
+  shouldUpdateWorldState,
 } from "../services/deepseek";
 import type {
   Story,
@@ -359,11 +361,26 @@ export default function GamePage() {
         );
       }
 
+      // Update world state for better character tracking
+      let newWorldState = session.worldState;
+      if (shouldUpdateWorldState(allMessages.length, session.worldState)) {
+        try {
+          newWorldState = await updateWorldState(
+            story,
+            allMessages,
+            session.worldState,
+          );
+        } catch (e) {
+          console.warn("Failed to update world state:", e);
+        }
+      }
+
       const finalSession: GameSession = {
         ...session,
         messages: allMessages,
         keyEvents: newKeyEvents,
         storySummary: newSummary,
+        worldState: newWorldState,
       };
 
       await apiSaveSession(story.id, currentSessionId, finalSession);
@@ -545,9 +562,24 @@ export default function GamePage() {
         assistantMessage,
       ];
 
+      // Update world state after edit regeneration
+      let newWorldState = session.worldState;
+      if (shouldUpdateWorldState(allMessages.length, session.worldState)) {
+        try {
+          newWorldState = await updateWorldState(
+            story,
+            allMessages,
+            session.worldState,
+          );
+        } catch (e) {
+          console.warn("Failed to update world state:", e);
+        }
+      }
+
       const finalSession: GameSession = {
         ...session,
         messages: allMessages,
+        worldState: newWorldState,
       };
 
       await apiSaveSession(story.id, currentSessionId, finalSession);