fix: use status update API as fallback for resolve ticket notes

The non-streaming fallback used getDocumentation which relies on
session.steps — empty for chat sessions, producing only the bare
resolution_summary text. Switch fallback to generateStatusUpdate
which reads conversation_messages and generates proper context-aware
ticket notes for both chat and guided sessions.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/components/assistant/ConcludeSessionModal.tsx

@@ -135,10 +135,13 @@ export function ConcludeSessionModal({
           (err) => {
             setStreaming(false)
             setStreamError(err)
-            // Try non-streaming fallback
-            aiSessionsApi.getDocumentation(sessionId).then((doc) => {
-              const fallback = `## Problem Summary\n${doc.problem_summary}\n\n## Steps Taken\n${doc.diagnostic_steps.map(s => `- ${s.description}`).join('\n')}\n\n## Resolution\n${doc.resolution_summary || 'See conversation'}\n\n## Next Steps\nNone`
-              setSummary(fallback)
+            // Fallback: use status update API which works with conversation context
+            aiSessionsApi.generateStatusUpdate(sessionId, {
+              audience: 'ticket_notes',
+              length: 'detailed',
+              context: 'resolution',
+            }).then((result) => {
+              setSummary(result.content)
               setStreamError(null)
             }).catch(() => {
               if (!summaryRef.current) {