feat(ai): add summary strategy with brief and standard detail levels

Support two summary strategies (brief/standard) for AI-generated session
summaries. Users can choose their preferred detail level in Settings > AI >
Session Index. Standard (default) produces richer summaries covering people,
events, and key details.

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/desktop/preload/apis/utils.ts

@@ -284,9 +284,10 @@ export const sessionApi = {
     dbSessionId: string,
     chatSessionId: number,
     locale?: string,
-    forceRegenerate?: boolean
+    forceRegenerate?: boolean,
+    strategy?: 'brief' | 'standard'
   ): Promise<{ success: boolean; summary?: string; error?: string }> => {
-    return ipcRenderer.invoke('session:generateSummary', dbSessionId, chatSessionId, locale, forceRegenerate)
+    return ipcRenderer.invoke('session:generateSummary', dbSessionId, chatSessionId, locale, forceRegenerate, strategy)
   },
 
   /**