diff --git a/backend/alembic.ini b/backend/alembic.ini
index adce95b3..018ab441 100644
--- a/backend/alembic.ini
+++ b/backend/alembic.ini
@@ -1,6 +1,8 @@
 [alembic]
 script_location = alembic
 prepend_sys_path = .
+# Split the path list the way the OS does (alembic's legacy space/comma/colon split is deprecated).
+path_separator = os
 
 [loggers]
 keys = root,sqlalchemy,alembic
diff --git a/backend/requirements-dev.txt b/backend/requirements-dev.txt
index bc9c558d..6f25a4da 100644
--- a/backend/requirements-dev.txt
+++ b/backend/requirements-dev.txt
@@ -1,7 +1,9 @@
 # Test + lint tooling — NEVER in the prod image. Installed only by backend/Dockerfile.test (the
 # throwaway test image), which the prod build (root Dockerfile) never references. Pinned so the
 # suite is reproducible: pytest for the pure-logic tests, and ruff at the SAME version the gate's
-# backend lint lane currently runs on the host (see the run_lint note in siftlode.sh). httpx is
-# already an app dependency (requirements.txt), so its TestClient needs nothing extra here.
+# backend lint lane runs on the host (the gate fails when the host's ruff is not this one). httpx2:
+# Starlette 1.x's TestClient is built on it (`import httpx2 as httpx`) and only falls back to the
+# app's own httpx with a deprecation warning on every run.
 pytest==8.4.2
 ruff==0.15.21
+httpx2==2.13.0
diff --git a/frontend/src/components/Home.dom.test.tsx b/frontend/src/components/Home.dom.test.tsx
index bd2bce1f..50017494 100644
--- a/frontend/src/components/Home.dom.test.tsx
+++ b/frontend/src/components/Home.dom.test.tsx
@@ -49,6 +49,7 @@ vi.mock("../lib/api", () => ({
     setState: () => Promise.resolve(),
     watchLaterAdd: () => Promise.resolve(),
     watchLaterRemove: () => Promise.resolve(),
+    downloadIndex: () => Promise.resolve({}), // the cards' download buttons read it
   },
   DISCOVER_BUDGETS: ["short", "medium", "long", "any"],
   discoverCardKey: (c: { source: string; id: string }) => `${c.source}:${c.id}`,
diff --git a/frontend/src/components/Home.pin.dom.test.tsx b/frontend/src/components/Home.pin.dom.test.tsx
index e3fc616a..9b122160 100644
--- a/frontend/src/components/Home.pin.dom.test.tsx
+++ b/frontend/src/components/Home.pin.dom.test.tsx
@@ -53,6 +53,7 @@ vi.mock("../lib/api", () => ({
     setState: () => Promise.resolve(),
     watchLaterAdd: () => Promise.resolve(),
     watchLaterRemove: () => Promise.resolve(),
+    downloadIndex: () => Promise.resolve({}), // the cards' download buttons read it
     comfortPins: (...a: unknown[]) => comfortPins(...a),
     addComfortPin: (...a: unknown[]) => addComfortPin(...a),
     removeComfortPin: (...a: unknown[]) => removeComfortPin(...a),
diff --git a/frontend/src/components/ui/Modal.fullscreen.dom.test.tsx b/frontend/src/components/ui/Modal.fullscreen.dom.test.tsx
index 816fd154..ac1bb3fe 100644
--- a/frontend/src/components/ui/Modal.fullscreen.dom.test.tsx
+++ b/frontend/src/components/ui/Modal.fullscreen.dom.test.tsx
@@ -31,7 +31,7 @@ describe("a dialog open while fullscreen is left", () => {
   it("keeps what the viewer had typed in it, and the focus inside it", async () => {
     const stage = document.createElement("div");
     document.body.appendChild(stage);
-    await setFullscreen(stage);
+    setFullscreen(stage);
     render(
       <Modal title="Download" onClose={() => {}}>
         <input aria-label="name" defaultValue="" />
@@ -42,7 +42,7 @@ describe("a dialog open while fullscreen is left", () => {
     field.focus();
     expect(stage.contains(field)).toBe(true);
 
-    await setFullscreen(null); // the browser's own Esc leaves fullscreen; the dialog stays open
+    setFullscreen(null); // the browser's own Esc leaves fullscreen; the dialog stays open
 
     const after = screen.getByLabelText("name") as HTMLInputElement;
     expect(after.value).toBe("my cut");
@@ -78,7 +78,7 @@ describe("a dialog with an autoFocus child", () => {
     const field = screen.getByLabelText("query");
     expect(document.activeElement).toBe(field);
 
-    await setFullscreen(stage); // the player goes fullscreen under the open dialog
+    setFullscreen(stage); // the player goes fullscreen under the open dialog
 
     expect(stage.contains(field)).toBe(true);
     expect(document.activeElement).toBe(field);
diff --git a/frontend/src/components/ui/QueryState.dom.test.tsx b/frontend/src/components/ui/QueryState.dom.test.tsx
index 089e147b..0b18581c 100644
--- a/frontend/src/components/ui/QueryState.dom.test.tsx
+++ b/frontend/src/components/ui/QueryState.dom.test.tsx
@@ -8,6 +8,9 @@ import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
 import { render, cleanup } from "@testing-library/react";
 import { LoadingState } from "./QueryState";
 
+// The label is not under test; without an i18n instance react-i18next warns on every render.
+vi.mock("react-i18next", () => ({ useTranslation: () => ({ t: (key: string) => key }) }));
+
 let now = 0;
 beforeEach(() => {
   vi.spyOn(performance, "now").mockImplementation(() => now);