feat(dashboard): fall back to document-text heroicon when no thumbnail yet

Uses the same heroicon as DocumentThumbnail so the "no thumbnail yet"
signal reads identically across the app: one shape, one meaning. The
parchment SVG still lives on in the fully-empty state (no resume doc
at all), where it represents a different thing — we removed it only
from the "document exists, thumbnail not generated yet" branch (#309).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

frontend/src/lib/components/DashboardResumeStrip.svelte

@@ -56,6 +56,27 @@ function safeColor(color: string): string {
 					loading="lazy"
 					decoding="async"
 				/>
+			{:else}
+				<div
+					data-testid="resume-thumbnail-fallback"
+					class="flex h-full w-full items-center justify-center text-ink-3"
+					aria-hidden="true"
+				>
+					<svg
+						xmlns="http://www.w3.org/2000/svg"
+						fill="none"
+						viewBox="0 0 24 24"
+						stroke-width="1.5"
+						stroke="currentColor"
+						class="h-16 w-16"
+					>
+						<path
+							stroke-linecap="round"
+							stroke-linejoin="round"
+							d="M19.5 14.25v-2.625a3.375 3.375 0 0 0-3.375-3.375h-1.5A1.125 1.125 0 0 1 13.5 7.125v-1.5a3.375 3.375 0 0 0-3.375-3.375H8.25m2.25 0H5.625c-.621 0-1.125.504-1.125 1.125v17.25c0 .621.504 1.125 1.125 1.125h12.75c.621 0 1.125-.504 1.125-1.125V11.25a9 9 0 0 0-9-9Z M9 12.75h6M9 15.75h6M9 18.75h3"
+						/>
+					</svg>
+				</div>
 			{/if}
 		</div>
 

frontend/src/lib/components/DashboardResumeStrip.svelte.spec.ts

@@ -69,4 +69,11 @@ describe('DashboardResumeStrip', () => {
 		await expect.element(img).toHaveAttribute('loading', 'lazy');
 		await expect.element(img).toHaveAttribute('decoding', 'async');
 	});
+
+	it('renders fallback icon when thumbnailUrl is null', async () => {
+		render(DashboardResumeStrip, { resumeDoc: mockResume });
+		const fallback = page.getByTestId('resume-thumbnail-fallback');
+		await expect.element(fallback).toBeInTheDocument();
+		await expect.element(page.getByTestId('resume-thumbnail-img')).not.toBeInTheDocument();
+	});
 });