fix(ui): add independent scroll containers to fix scroll wheel on Linux

Providers page was using DndContext which may interfere with scroll wheel
events on Linux/Ubuntu WebKitGTK. Added independent scroll containers
with `overflow-y-auto` to all main pages, matching the pattern already
used by the MCP panel which works correctly.

Changes:
- App.tsx: Wrap ProviderList in independent scroll container
- SkillsPage: Use consistent h-[calc(100vh-8rem)] layout
- SettingsPage: Add overflow-hidden and overflow-x-hidden for consistency

src/App.tsx

@@ -303,20 +303,25 @@ function App() {
         return <AgentsPanel onOpenChange={() => setCurrentView("providers")} />;
       default:
         return (
-          <div className="mx-auto max-w-[56rem] px-6 space-y-4">
-            <ProviderList
-              providers={providers}
-              currentProviderId={currentProviderId}
-              appId={activeApp}
-              isLoading={isLoading}
-              onSwitch={switchProvider}
-              onEdit={setEditingProvider}
-              onDelete={setConfirmDelete}
-              onDuplicate={handleDuplicateProvider}
-              onConfigureUsage={setUsageProvider}
-              onOpenWebsite={handleOpenWebsite}
-              onCreate={() => setIsAddOpen(true)}
-            />
+          <div className="mx-auto max-w-[56rem] px-6 flex flex-col h-[calc(100vh-8rem)] overflow-hidden">
+            {/* 独立滚动容器 - 解决 Linux/Ubuntu 下 DndContext 与滚轮事件冲突 */}
+            <div className="flex-1 overflow-y-auto overflow-x-hidden pb-12">
+              <div className="space-y-4">
+                <ProviderList
+                  providers={providers}
+                  currentProviderId={currentProviderId}
+                  appId={activeApp}
+                  isLoading={isLoading}
+                  onSwitch={switchProvider}
+                  onEdit={setEditingProvider}
+                  onDelete={setConfirmDelete}
+                  onDuplicate={handleDuplicateProvider}
+                  onConfigureUsage={setUsageProvider}
+                  onOpenWebsite={handleOpenWebsite}
+                  onCreate={() => setIsAddOpen(true)}
+                />
+              </div>
+            </div>
           </div>
         );
     }