test(web): add E2E for Fleet route nav + per-instance row render

Two focused Playwright tests, mirroring the existing sidebar.spec
pattern (no backend dependency — instances point at unreachable ports
and we only assert on rendered names + row count, not health):

- Fleet link in the sidebar navigates to /fleet
- /fleet renders one row per configured instance under the table role

Also adds a Fleet link assertion to the existing sidebar.spec so the
nav entry is covered on the dashboard route alongside the other top
links. Both new tests run under the existing `pnpm test:e2e` (not
gated in CI by design — matches the current Compare/Dashboard E2E
posture).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

packages/web/e2e/sidebar.spec.ts

@@ -17,6 +17,7 @@ test.describe("Sidebar", () => {
 		await page.goto("/");
 		await expect(page.getByRole("complementary")).toBeVisible();
 		await expect(page.getByRole("link", { name: /dashboard/i })).toBeVisible();
+		await expect(page.getByRole("link", { name: /fleet/i })).toBeVisible();
 		await expect(page.getByRole("link", { name: /workspaces/i })).toBeVisible();
 		await expect(page.getByRole("link", { name: /settings/i })).toBeVisible();
 	});