Clean: remove Playwright code, keep scoring fix and fallback threshold

hf_backend/fetcher.py

@@ -286,59 +286,7 @@ def _download_from_src_a(
             except Exception:
                 continue
 
-    with sync_playwright() as p:
-        browser = p.chromium.launch(headless=True)
-        context = browser.new_context(
-            user_agent="Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36",
-            accept_downloads=True,
-        )
-        page = context.new_page()
-
-        try:
-            page.goto(url, timeout=60_000, wait_until="domcontentloaded")
-
-            # Wait for the countdown timer to finish and a download link to appear
-            for elapsed in range(wait_seconds):
-                time.sleep(1)
-
-                # Check if page navigated away (redirect to download)
-                current = page.url
-                if current != url and "slow_download" not in current and "fast_download" not in current:
-                    # Direct redirect — fetch via requests using cookies from the browser
-                    break
-
-                # Check for download links that appeared after countdown
-                try:
-                    links = page.query_selector_all("a[href]")
-                    for link in links:
-                        href = link.get_attribute("href") or ""
-                        text = (link.text_content() or "").strip().lower()
-                        if ("get.php" in href or href.endswith(".epub") or
-                                ("download" in text and href and href != "#")):
-                            # Try to capture download
-                            try:
-                                with page.expect_download(timeout=5_000) as dl_info:
-                                    link.click()
-                                dl = dl_info.value
-                                dl_path = dl.path()
-                                if dl_path:
-                                    with open(dl_path, "rb") as f:
-                                        return f.read()
-                            except Exception:
-                                # click didn't trigger download, try fetching URL directly
-                                abs_href = href if href.startswith("http") else f"https://annas-archive.gl{href}"
-                                resp = context.request.get(abs_href, timeout=120_000)
-                                if resp.status == 200 and len(resp.body()) > 1000:
-                                    return resp.body()
-                except Exception:
-                    pass
-
-        except Exception:
-            pass
-        finally:
-            browser.close()
-
-    return None
+    raise FetchError("所有下载方式均失败（Libgen 和 Anna's Archive）")
 
 
 def _download_from_src_b(