fix: tag counts, chip focus, upload naming, share links and unsized clips hold after round 2

- A tag counts the followed channels the Subscriptions tab shows: hidden ones are left out, and a
  subscribe, unsubscribe, hide or tag toggle refreshes the count. The Tag manager's row and its
  hover list count the same channels as the chip; /api/tags sends both counts under their names.
- A chip's count keeps the chip's colour after a dot (a dimmed count fell under 4.5:1). A pick in
  the open "+N" fold closes it; a chip that leaves the list hands the focus to the one in its place.
  The fold is a dialog of toggle buttons, not an empty menu.
- Upload: a folder name left by a press is made once the press is over, if the dialog is still
  open, instead of guessing a dismissal from Modal's markup. While the folder is made, its place
  holds the focus and a live region says so.
- Share: an expired link has no Copy and a warn badge; the link made on open goes into the cached
  list, so a reopen makes no second one; the New link form survives the link made on open.
- Watch: a repeated Enter sends one unlock while one is on its way. See all buttons are named with
  their rail.
- An unsized clip of a rotated file gets the upright size its crop cut.

frontend/src/watch/WatchPage.dom.test.tsx

@@ -294,6 +294,22 @@ describe("WatchPage honest failures", () => {
     expect(page.getByRole("button", { name: button })).toBeTruthy();
   });
 
+  it("a repeated Enter sends one try while it is on its way", async () => {
+    window.history.replaceState({}, "", "/watch/tok-enter");
+    const fetchMock = vi.fn().mockResolvedValueOnce(res(200, { needs_password: true }));
+    fetchMock.mockImplementation(() => new Promise(() => {}));
+    vi.stubGlobal("fetch", fetchMock);
+    const page = render(<WatchPage />);
+    const field = await page.findByPlaceholderText("Enter password");
+    fireEvent.change(field, { target: { value: "guess" } });
+    fireEvent.keyDown(field, { key: "Enter" });
+    await waitFor(() => expect(fetchMock).toHaveBeenCalledTimes(2));
+    fireEvent.keyDown(field, { key: "Enter" });
+    fireEvent.keyDown(field, { key: "Enter" });
+    await new Promise((r) => setTimeout(r, 20));
+    expect(fetchMock).toHaveBeenCalledTimes(2);
+  });
+
   it("too many password tries says so, and keeps the form", async () => {
     window.history.replaceState({}, "", "/watch/tok-429");
     const page = await tryPassword(async () => res(429));