feat(web): unify panel loading states with grid spinner (#1142)

apps/web/components/panel-loading-state.tsx

@@ -0,0 +1,30 @@
+"use client";
+
+import { GridSpinner } from "@/components/grid-spinner";
+import { cn } from "@/lib/utils";
+
+type PanelLoadingStateProps = {
+  label: string;
+  /** Override the outer container layout (e.g. absolute overlay for the terminal). */
+  className?: string;
+  testId?: string;
+};
+
+/**
+ * Shared panel loading placeholder: a grid spinner above a label, matching the
+ * terminal's "Connecting terminal..." look. Used by the file browser, terminal,
+ * and agent preview panels so loading states stay visually consistent.
+ */
+export function PanelLoadingState({ label, className, testId }: PanelLoadingStateProps) {
+  return (
+    <div
+      data-testid={testId}
+      className={cn("flex h-full w-full items-start justify-center pt-12", className)}
+    >
+      <div className="flex flex-col items-center gap-3 text-muted-foreground">
+        <GridSpinner />
+        <span className="text-sm">{label}</span>
+      </div>
+    </div>
+  );
+}

apps/web/components/task/file-browser-load-state.tsx

@@ -1,6 +1,6 @@
 "use client";
 
-import { IconLoader2 } from "@tabler/icons-react";
+import { PanelLoadingState } from "@/components/panel-loading-state";
 import type { FileTreeNode } from "@/lib/types/backend";
 
 type RenderSessionOrLoadStateInput = {
@@ -31,18 +31,10 @@ export function renderSessionOrLoadState({
     );
   }
   if ((loadState === "loading" || isLoadingTree) && !tree) {
-    return <div className="p-4 text-sm text-muted-foreground">Loading files...</div>;
+    return <PanelLoadingState label="Loading files..." />;
   }
   if (loadState === "waiting") {
-    return (
-      <div
-        data-testid="file-tree-waiting"
-        className="p-4 text-sm text-muted-foreground flex items-center gap-2"
-      >
-        <IconLoader2 className="h-3.5 w-3.5 animate-spin" />
-        Preparing workspace...
-      </div>
-    );
+    return <PanelLoadingState testId="file-tree-waiting" label="Preparing workspace..." />;
   }
   if (loadState === "manual") {
     return (

apps/web/components/task/passthrough-terminal.tsx

@@ -6,7 +6,7 @@ import { FitAddon } from "@xterm/addon-fit";
 import { AttachAddon } from "@xterm/addon-attach";
 import { WebglAddon } from "@xterm/addon-webgl";
 import "@xterm/xterm/css/xterm.css";
-import { GridSpinner } from "@/components/grid-spinner";
+import { PanelLoadingState } from "@/components/panel-loading-state";
 import { useAppStore } from "@/components/state-provider";
 import { useSession } from "@/hooks/domains/session/use-session";
 import { useSessionAgentctl } from "@/hooks/domains/session/use-session-agentctl";
@@ -277,17 +277,11 @@ export function PassthroughTerminal(props: PassthroughTerminalProps) {
       </div>
       <TerminalSearchBar search={search} />
       {!isConnected && (
-        <div
-          data-testid="passthrough-loading"
-          className="absolute inset-0 flex items-start justify-center pt-12 bg-background"
-        >
-          <div className="flex flex-col items-center gap-3 text-muted-foreground">
-            <GridSpinner />
-            <span className="text-sm">
-              {mode === "agent" ? "Preparing workspace..." : "Connecting terminal..."}
-            </span>
-          </div>
-        </div>
+        <PanelLoadingState
+          testId="passthrough-loading"
+          className="absolute inset-0 bg-background"
+          label={mode === "agent" ? "Preparing workspace..." : "Connecting terminal..."}
+        />
       )}
     </div>
   );

apps/web/components/task/preview-session-tabs.tsx

@@ -1,10 +1,10 @@
 "use client";
 
 import { useCallback, useMemo } from "react";
-import { IconLoader2 } from "@tabler/icons-react";
 import { Button } from "@kandev/ui/button";
 import { AgentLogo } from "@/components/agent-logo";
 import { GridSpinner } from "@/components/grid-spinner";
+import { PanelLoadingState } from "@/components/panel-loading-state";
 import { SessionTabs, type SessionTab } from "@/components/session-tabs";
 import { useAppStore } from "@/components/state-provider";
 import { useToast } from "@/components/toast-provider";
@@ -177,15 +177,7 @@ function RunningSpinner() {
 }
 
 function PreviewLoadingState({ label }: { label: string }) {
-  return (
-    <div
-      className="flex h-full items-center justify-center gap-2 text-sm text-muted-foreground"
-      data-testid="preview-loading-state"
-    >
-      <IconLoader2 className="h-4 w-4 animate-spin" />
-      {label}
-    </div>
-  );
+  return <PanelLoadingState testId="preview-loading-state" label={label} />;
 }
 
 function PreviewEmptyState() {