docs(plugin): add light and dark registry screenshots

README.md

@@ -12,6 +12,13 @@ version, title, author, repository, description and supported platforms),
 `src/index.ts` (manifest, navigation and routes), and `src/page.ts` (sidebar UI).
 The example serves its page at `/ui/` and preserves JSON at `/`.
 
+The registry previews come from `temps.screenshots` in `package.json`. Replace
+the light/dark PNGs in `assets/` with screenshots of your own plugin, and update
+each repository-relative `path`, descriptive `alt`, and optional `caption`.
+Capture only the plugin UI: never include credentials, account details, or
+private project data. The catalog resolves these paths at the plugin's pinned
+Git commit; changes appear after merging and refreshing the GitHub catalog.
+
 ```sh
 bun install --frozen-lockfile
 bun test

package.json

@@ -18,6 +18,18 @@
     "title": "My plugin",
     "category": "Development",
     "entrypoint": "src/index.ts",
+    "screenshots": [
+      {
+        "path": "assets/plugin-light.png",
+        "alt": "My plugin in light mode, showing its online status and hello-world API response",
+        "caption": "The starter plugin running inside Temps in light mode."
+      },
+      {
+        "path": "assets/plugin-dark.png",
+        "alt": "My plugin in dark mode, showing its online status and hello-world API response",
+        "caption": "The same plugin UI adapts to dark mode."
+      }
+    ],
     "platforms": ["linux-amd64-gnu", "linux-arm64-gnu", "linux-amd64-musl", "linux-arm64-musl", "darwin-amd64", "darwin-arm64"]
   }
 }

src/screenshots.test.ts

@@ -0,0 +1,17 @@
+// SPDX-FileCopyrightText: 2024-2026 Temps Contributors
+// SPDX-License-Identifier: MIT OR Apache-2.0
+import { expect, test } from "bun:test";
+import pkg from "../package.json";
+
+test("registry screenshots reference real PNG assets with accessible descriptions", async () => {
+  expect(pkg.temps.screenshots).toHaveLength(2);
+  for (const screenshot of pkg.temps.screenshots) {
+    expect(screenshot.path).toMatch(/^assets\/[a-z-]+\.png$/);
+    expect(screenshot.alt.length).toBeGreaterThan(20);
+    const image = Bun.file(new URL(`../${screenshot.path}`, import.meta.url));
+    expect(await image.exists()).toBe(true);
+    const bytes = new Uint8Array(await image.arrayBuffer());
+    expect(Array.from(bytes.slice(0, 8))).toEqual([137, 80, 78, 71, 13, 10, 26, 10]);
+    expect(bytes.length).toBeLessThan(500_000);
+  }
+});