Bump CSAT debounce to 15s

Give the user more room to keep chatting before the rating prompt
interrupts.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Author: nedasvi

ui/src/main/kotlin/app/resolvekit/ui/ResolveKitRuntime.kt

@@ -773,7 +773,7 @@ class ResolveKitRuntime(
     private fun scheduleFeedbackPrompt() {
         feedbackPromptDelayJob?.cancel()
         feedbackPromptDelayJob = scope.launch {
-            delay(6_000)
+            delay(15_000)
             _pendingFeedbackRequest.value = true
         }
     }