fix: correct AI contextualization method call

- Fix method name from generateContextualization to getContextualization
- Pass passage excerpt (first 200 chars) as required third parameter
- This should fix the metadata field showing fallback text

src/clozeGameEngine.js

@@ -333,9 +333,10 @@ class ClozeGame {
   async generateContextualization() {
     // Always use AI for contextualization
     try {
-      this.contextualization = await aiService.generateContextualization(
+      this.contextualization = await aiService.getContextualization(
         this.currentBook.title,
-        this.currentBook.author
+        this.currentBook.author,
+        this.originalText.substring(0, 200) // Pass first 200 chars of passage
       );
       return this.contextualization;
     } catch (error) {