Point classic UI at mounted /servers.json in Docker entrypoint (#870)

* Initial plan

* Apply remaining changes

Co-authored-by: sstidl <12804296+sstidl@users.noreply.github.com>

* Apply remaining changes

Co-authored-by: sstidl <12804296+sstidl@users.noreply.github.com>

* Reuse SERVER_LIST_URL sed block for mounted servers.json

Co-authored-by: sstidl <12804296+sstidl@users.noreply.github.com>

* Strengthen classic mounted server list E2E assertions

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: sstidl <12804296+sstidl@users.noreply.github.com>
Co-authored-by: Stefan Stidl <sti-github@stidl.com>

docker/entrypoint.sh

@@ -91,6 +91,8 @@ if [[ "$MODE" == "frontend" || "$MODE" == "dual" ||  "$MODE" == "standalone" ]];
   if [ -f /servers.json ]; then
     echo "using mounted /servers.json for server-list.json"
     cp /servers.json /var/www/html/server-list.json
+    # default the frontend list to the mounted file so the classic design uses it too
+    SERVER_LIST_URL="${SERVER_LIST_URL:-server-list.json}"
   elif [ -n "$SERVER_LIST_URL" ]; then
     echo "no /servers.json found, relying on SERVER_LIST_URL"
   elif [ "$MODE" == "frontend" ]; then

tests/e2e/classic-server-list.spec.js

@@ -0,0 +1,29 @@
+const { test, expect } = require("@playwright/test");
+const { baseUrls } = require("./helpers/env");
+
+test.describe("Classic design with mounted server list", () => {
+  test("frontend classic page loads the mounted server-list.json", async ({ page, request }) => {
+    const html = await (await request.get(`${baseUrls.frontend}/index-classic.html`)).text();
+    expect(html).toMatch(/var SPEEDTEST_SERVERS = "server-list\.json";/);
+
+    const pageErrors = [];
+    page.on("pageerror", error => pageErrors.push(error.message));
+
+    // This fixture hostname only resolves inside Docker. Keep server selection
+    // deterministic without mocking the mounted server-list.json response.
+    await page.route("http://backend-testpoint:8080/empty.php*", route =>
+      route.fulfill({ status: 200, headers: { "Access-Control-Allow-Origin": "*" }, body: "" })
+    );
+
+    const listResponse = page.waitForResponse(response => response.url().endsWith("/server-list.json"));
+    await page.goto(`${baseUrls.frontend}/index-classic.html`);
+
+    const response = await listResponse;
+    expect(response.ok()).toBeTruthy();
+
+    // Verify the fetched config was applied to the classic server selector.
+    await expect(page.locator("#server option")).toHaveText(["Backend testpoint"], { timeout: 10_000 });
+    await expect(page.locator("#startStopBtn")).toBeVisible();
+    expect(pageErrors).toEqual([]);
+  });
+});