fix(desktop): DeerFlow UI — ChatArea refactor + ai-elements + dead CSS cleanup

ChatArea retry button uses setInput instead of direct sendToGateway,
fix bootstrap spinner stuck for non-logged-in users,
remove dead CSS (aurora-title/sidebar-open/quick-action-chips),
add ai components (ReasoningBlock/StreamingText/ChatMode/ModelSelector/TaskProgress),
add ClassroomPlayer + ResizableChatLayout + artifact panel

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

desktop/src/store/saasStore.ts

@@ -536,6 +536,27 @@ export const useSaaSStore = create<SaaSStore>((set, get) => {
         // Update last sync timestamp
         localStorage.setItem(lastSyncKey, result.pulled_at);
         log.info(`Synced ${result.configs.length} config items from SaaS`);
+
+        // Propagate Kernel-relevant configs to Rust backend
+        const kernelCategories = ['agent', 'llm'];
+        const kernelConfigs = result.configs.filter(
+          (c) => kernelCategories.includes(c.category) && c.value !== null
+        );
+        if (kernelConfigs.length > 0) {
+          try {
+            const { invoke } = await import('@tauri-apps/api/core');
+            await invoke('kernel_apply_saas_config', {
+              configs: kernelConfigs.map((c) => ({
+                category: c.category,
+                key: c.key,
+                value: c.value,
+              })),
+            });
+            log.info(`Propagated ${kernelConfigs.length} Kernel configs to Rust backend`);
+          } catch (invokeErr: unknown) {
+            log.warn('Failed to propagate configs to Kernel (non-fatal):', invokeErr);
+          }
+        }
       } catch (err: unknown) {
         log.warn('Failed to sync config from SaaS:', err);
       }