feat(ui): add animated paperclip page loaders (#10456)

## Thinking Path

> - Paperclip is the open source control plane people use to manage AI
agents for work
> - Operators regularly pass through full-page loading states while
authentication and company context resolve
> - Those states currently render as small bare text, which is easy to
miss and does not reinforce Paperclip's visual identity
> - A shared loading component gives these transitions one accessible,
consistent representation
> - This pull request introduces an animated paperclip loader and uses
it at the existing full-page loading boundaries
> - The benefit is a clearer, calmer loading experience with
reduced-motion and screen-reader support

## Linked Issues or Issue Description

### Subsystem affected

`ui/` — React + Vite board UI

### Problem or motivation

Full-page authentication, access-gate, and company-context waits use
small bare `Loading…` text that is visually weak and inconsistent.

### Proposed solution

Use one large centered paperclip loader at those boundaries, drawing the
SVG with `currentColor` so it follows the active theme.

### Alternatives considered

Keeping text-only states or adding a generic spinner would preserve less
of Paperclip's product identity and would continue duplicating loading
markup.

### Roadmap alignment

This is tightly scoped UI polish and does not duplicate a planned
roadmap capability.

### Additional context

Internal coordination task PAP-15760 requested this focused change.

## What Changed

- Added `AnimatedPaperclipIcon`, a theme-aware SVG whose stroke draws in
a loop.
- Added `PaperclipLoading`, a large full-viewport centered loader with
`role="status"` and an `sr-only` `Loading…` label.
- Added a static fully drawn fallback under `prefers-reduced-motion:
reduce`.
- Replaced bare loading text in `CloudAccessGate`, the Auth session
check, and three company-context redirects.
- Used token-safe Tailwind utilities throughout the component.
- Added focused coverage for the status semantics and the Auth layout
height override.

## Verification

- `pnpm check:token-gates`
- `pnpm -C ui exec tsc -b`
- `pnpm -C ui exec vitest run
src/components/AnimatedPaperclipIcon.test.tsx`
- `pnpm -C ui exec vitest run src/App.test.tsx
src/App.cases-routing.test.tsx` — 8/8 tests passed
- Visually checked light and dark loading states; the screenshot below
shows both themes.

![Large centered paperclip loading state in light and dark
themes](https://pages.paperclip.ing/pap-15760-loading-state/pap15760-loading.png)

## Risks

- Low risk: this changes presentation only at existing loading branches.
- Motion-sensitive users receive a static, fully drawn paperclip through
the reduced-motion media query.
- Screen readers retain a concise loading announcement through the
status role and visually hidden label.

> For core feature work, check [`ROADMAP.md`](ROADMAP.md) first and
discuss it in `#dev` before opening the PR. Feature PRs that overlap
with planned core work may need to be redirected — check the roadmap
first. See `CONTRIBUTING.md`.

## Model Used

- OpenAI Codex, GPT-5 (exact service build ID and context-window size
are not exposed in this environment), with reasoning, repository
inspection, shell tool use, code execution, and image inspection.

## Checklist

- [x] I have included a thinking path that traces from project context
to this change
- [x] I have specified the model used with all deployment details
available to this environment
- [x] I have checked ROADMAP.md and confirmed this PR does not duplicate
planned core work
- [x] I have searched GitHub for duplicate or related PRs and found none
- [x] I have described the issue in-PR following the feature-request
fields
- [x] I included the task-mandated internal parent reference and no
private instance URL
- [x] I preserved the task-mandated existing branch name without
renaming it
- [x] I have run scoped tests locally and they pass
- [x] I added focused component coverage for the new loading state
- [x] No documentation update is required for this presentation-only
change
- [x] I have considered and documented the risks above
- [x] All Paperclip CI gates are green
- [x] Greptile is 5/5 with no open P2s, recommendations, or follow-ups
- [x] I will address all Greptile and reviewer comments before
requesting merge

Co-authored-by: Paperclip <noreply@paperclip.ing>

ui/src/components/AnimatedPaperclipIcon.test.tsx

@@ -0,0 +1,23 @@
+// @vitest-environment node
+
+import { renderToStaticMarkup } from "react-dom/server";
+import { describe, expect, it } from "vitest";
+import { PaperclipLoading } from "./AnimatedPaperclipIcon";
+
+describe("PaperclipLoading", () => {
+  it("renders an accessible full-page loading state", () => {
+    const html = renderToStaticMarkup(<PaperclipLoading />);
+
+    expect(html).toContain('role="status"');
+    expect(html).toContain("min-h-dvh");
+    expect(html).toContain('aria-hidden="true"');
+    expect(html).toContain('<span class="sr-only">Loading…</span>');
+  });
+
+  it("allows containing layouts to override the full-page height", () => {
+    const html = renderToStaticMarkup(<PaperclipLoading className="min-h-0" />);
+
+    expect(html).toContain("min-h-0");
+    expect(html).not.toContain("min-h-dvh");
+  });
+});

ui/src/components/AnimatedPaperclipIcon.tsx

@@ -0,0 +1,36 @@
+import type { SVGProps } from "react";
+import { cn } from "../lib/utils";
+
+export function AnimatedPaperclipIcon({ className, ...props }: SVGProps<SVGSVGElement>) {
+  return (
+    <svg
+      viewBox="-1 -1 26 26"
+      className={cn("paperclip-thinking-icon", className)}
+      aria-hidden="true"
+      {...props}
+    >
+      <path
+        className="paperclip-thinking-icon-path"
+        d="M16 6 l-8.414 8.586 a2.000 2.000 0 0 0 2.828 2.828 l8.414 -8.586 a4.000 4.000 0 1 0 -5.657 -5.657 l-8.379 8.551 a6.000 6.000 0 1 0 8.485 8.485 l8.379 -8.551"
+        fill="none"
+        stroke="currentColor"
+        strokeWidth="2"
+        strokeLinecap="round"
+        strokeLinejoin="round"
+      />
+    </svg>
+  );
+}
+
+/** Full-page loading state: a large, centered, gray animated paperclip. */
+export function PaperclipLoading({ className }: { className?: string }) {
+  return (
+    <div
+      role="status"
+      className={cn("flex min-h-dvh w-full items-center justify-center", className)}
+    >
+      <AnimatedPaperclipIcon className="h-24 w-24 text-muted-foreground" />
+      <span className="sr-only">Loading…</span>
+    </div>
+  );
+}

ui/src/components/CloudAccessGate.tsx

@@ -6,6 +6,7 @@ import { authApi } from "@/api/auth";
 import { healthApi } from "@/api/health";
 import { queryKeys } from "@/lib/queryKeys";
 import { BootstrapPendingPage } from "@/components/BootstrapPendingPage";
+import { PaperclipLoading } from "@/components/AnimatedPaperclipIcon";
 import { Card } from "@/components/ui/card";
 
 function NoBoardAccessPage() {
@@ -74,7 +75,7 @@ export function CloudAccessGate() {
     (isAuthenticatedMode && sessionQuery.isLoading) ||
     (isAuthenticatedMode && !isBootstrapPending && !!sessionQuery.data && boardAccessQuery.isLoading)
   ) {
-    return <div className="mx-auto max-w-xl py-10 text-sm text-muted-foreground">Loading...</div>;
+    return <PaperclipLoading />;
   }
 
   if (healthQuery.error || boardAccessQuery.error) {
@@ -92,7 +93,7 @@ export function CloudAccessGate() {
   if (isBootstrapPending) {
     const health = healthQuery.data;
     if (!health) {
-      return <div className="mx-auto max-w-xl py-10 text-sm text-muted-foreground">Loading...</div>;
+      return <PaperclipLoading />;
     }
     const claimError = claimMutation.error instanceof ApiError
       ? { status: claimMutation.error.status, message: claimMutation.error.message }