fix: share, upload, crop, auto-skip, tag chips and See all hold what they claim

- Share: a link that expired is never copied (the dialog and one-click Share pick a live one,
  else make one), says it expired, and the copy-on-open claim clears on the next copy.
- A password-protected file link asks to open a file, not to watch a video.
- Upload: Cancel, the close button or the backdrop while naming a folder makes no folder; a failed
  refetch keeps the target; a folder being made says so.
- Crop: an infinite number is dropped, not a 500; an unprobed clip's size follows a shown-size crop;
  the edit_spec docs name frame_w/frame_h; the join and rotated paths are tested.
- Auto-skip: the wait gives way on a marker too short for it, so the skip still fires.
- Tag chips count the followed channels (subscribed_count) and a toggled chip keeps the focus.
- Continue watching's See all sorts by last watched when in progress was already on.

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

@@ -281,6 +281,19 @@ describe("WatchPage honest failures", () => {
     return page;
   }
 
+  it.each([
+    [{ kind: "file", video: true }, "This video is password-protected", "Watch"],
+    [{ kind: "file", video: false }, "This file is password-protected", "Open"],
+    [{ kind: "folder", video: false }, "This folder is password-protected", "Open"],
+    [{}, "This video is password-protected", "Watch"],
+  ])("a password link that opens %o asks in its words", async (kind, title, button) => {
+    window.history.replaceState({}, "", "/file/tok-lock");
+    mockMeta({ needs_password: true, ...kind });
+    const page = render(<WatchPage />);
+    await page.findByText(title);
+    expect(page.getByRole("button", { name: button })).toBeTruthy();
+  });
+
   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));