帮我安装 Agent Reach：
https://raw.githubusercontent.com/
Panniantong/agent-reach/main/docs/install.md

class AgentReach:
    """Give your AI Agent eyes to see
    the entire internet.
    For reading/searching, use the
    upstream tools directly."""

    def doctor(self):
        # Check all channel availability.
        from agent_reach.doctor import check_all
        return check_all(self.config)

class Channel(ABC):
    name: str = ""          # "youtube"
    description: str = ""   # "YouTube 视频和字幕"
    backends: List[str] = []  # 候选后端列表
    tier: int = 0          # 0=零配置 2=要登录

    @abstractmethod
    def can_handle(self, url):
        # 这个网址归我管吗？
    def check(self, config):
        # 我的上游工具装好了吗？

for ch in get_all_channels():
    try:
        status, message = ch.check(config)
    except Exception as e:
        # 一个专员崩了，不能拖垮整张报告
        status, message = "error", f"体检异常：{e}"
    results[ch.name] = { "status": status, ... }

class BilibiliChannel(Channel):
    name = "bilibili"
    description = "B站视频、字幕和搜索"
    backends = ["bili-cli",
                "OpenCLI",
                "B站搜索 API"]

for backend in self.ordered_backends(config):
    if backend == "bili-cli":
        result = self._check_bili_cli()
    elif backend == "OpenCLI":
        result = self._check_opencli()
    else:
        result = self._check_search_api()
    if result is None:
        continue  # 这个没装，试下一个

candidates = list(self.backends)
override = config.get(f"{self.name}_backend")
if override:
    for i, b in enumerate(candidates):
        if b == override or b.startswith(override):
            candidates.insert(0, candidates.pop(i))
            break  # 找到了才插队；找不到就忽略

path = shutil.which(cmd)
if not path:
    return ProbeResult("missing")
try:
    r = subprocess.run([path, *args], timeout=timeout)
except FileNotFoundError:
    # which 找到了它，但执行失败：
    # 快捷方式指向的解释器没了
    return ProbeResult("broken", hint=reinstall_hint(package))

for _ in range(retries + 1):
    last = _run_once(path, args, timeout, package)
    if last.ok:
        return last
    # missing/broken 不会自己好——别浪费重试
    if last.status in ("missing", "broken"):
        return last

results = check_all(config)

if getattr(args, "json", False):
    print(json.dumps(results, ensure_ascii=False))
    return

rprint(format_report(results))  # 给人看的彩色报告

# 一开始就用严格权限创建文件，
# 避免有一瞬间凭据是"人人可读"的
fd = os.open(
    str(self.config_path),
    os.O_WRONLY | os.O_CREAT | os.O_TRUNC,
    stat.S_IRUSR | stat.S_IWUSR,  # 0o600 只有你能读写
)