fix(resources): normalize GitHub proxy and retry downloads

Reuse the checked resource manifest within each download and retain phase-specific retry errors. Preserve application update error contracts.

Refs #7185

tests/test_github_proxy_update.py

@@ -0,0 +1,38 @@
+"""
+验证 Python 更新器与 Docker 控制脚本使用相同的 GitHub 代理地址规则。
+"""
+
+import os
+import subprocess
+from pathlib import Path
+
+import pytest
+
+from app.adapters.system import update as update_module
+
+
+@pytest.mark.parametrize(
+    ("proxy", "prefix"),
+    [
+        ("", ""),
+        ("https://proxy.example", "https://proxy.example/"),
+        ("https://proxy.example/", "https://proxy.example/"),
+        (" https://proxy.example/path ", "https://proxy.example/path/"),
+        ("proxy.example/path", "http://proxy.example/path/"),
+    ],
+)
+def test_update_proxy_prefix_matches_docker(monkeypatch, tmp_path, proxy, prefix):
+    """
+    代理首尾空白、路径及尾斜杠兼容规则在两种部署更新入口保持一致。
+    """
+    url = "https://github.com/jxxghp/MoviePilot/archive/refs/tags/v3.1.9.zip"
+    monkeypatch.setattr(update_module, "get_runtime_setting", lambda _key: proxy)
+    updater = Path(__file__).resolve().parents[1] / "docker" / "update.sh"
+    result = subprocess.run(
+        ["/bin/bash", "-c", 'source "$1"; github_download_url "$2"', "proxy-test", str(updater), url],
+        env={**os.environ, "GITHUB_PROXY": proxy, "CONFIG_DIR": str(tmp_path)},
+        text=True, capture_output=True, check=True,
+    )
+
+    assert result.stdout.strip() == prefix + url
+    assert update_module.SystemUpdateManager._proxied(url) == prefix + url