Add repository traffic/insights tools (views, clones, referrers, paths)

先閱讀 repos 工具集中的現有工具，以及固定版本 go-github 中的 ListTrafficViews、ListTrafficClones、ListTrafficReferrers 和 ListTrafficPaths 方法。新增這四個唯讀工具，並使用所述參數和儲存庫範圍要求；然後驗證 views 和 clones 接受按日或按週的細分，而 referrers 和 paths 不接受。

Describe the feature or problem you'd like to solve

The server has no way to read a repository's traffic/insights data. There are no tools wrapping the four traffic endpoints:

Today an agent can read stars and forks but has no view into whether a repo is actually being visited or cloned, which is the primary signal for measuring adoption and reach of a project. This is a read-only capability.

Proposed solution

Add the four tools above under the existing repos toolset, each ReadOnlyHint: true.

The implementation is thin because the pinned go-github client already exposes all four methods (RepositoriesService.ListTrafficViews, ListTrafficClones, ListTrafficReferrers, ListTrafficPaths), so no new HTTP plumbing is needed. The views/clones tools take an optional per parameter (day | week) mapping to TrafficBreakdownOptions; referrers/paths take just owner/repo.

One note on access: GitHub gates these endpoints behind push access to the repo (for GitHub Apps, the repository Administration: Read permission), so the tools should be annotated to require the repo scope rather than treated as public-read, even though the endpoints exist on public repos.

I'm happy to open a PR for this if the capability is something you'd accept.

Example prompts or workflows (for tools/toolsets only)

1. "How many unique visitors and clones did owner/repo get in the last two weeks?"
2. "Where is traffic to my repo coming from? Show me the top referrers."
3. "Which pages/paths in owner/repo are people actually viewing?"
4. "Compare views vs. clones week over week for owner/repo and tell me if adoption is trending up."
5. "Build me a weekly adoption report for my repo: stars, forks, views, unique visitors, and clones." (traffic is the missing piece today; stars/forks are already covered)

Additional context

Traffic data has a 14-day rolling retention window on GitHub's side, so these tools are especially useful to agents that snapshot the data on a schedule for longer-term trend tracking.