feat: add total release assets download count via /assets-dl/:owner/:repo/total

[gumaciel]

Problem

Currently, the GitHub assets download badge endpoint (/github/assets-dl/:owner/:repo/:tag?) only supports fetching downloads for the latest release (when tag is omitted) or for a specific release tag (e.g. /v7.0.0).

Users who want to display the total asset download count across recent releases cannot do so.

Solution

Add support for /github/assets-dl/:owner/:repo/total (and /all) to calculate total asset downloads for recent releases.

• Queries GET /repos/{owner}/{repo}/releases?per_page=30.
• Sums download_count for all assets found across the returned releases.
• Formats the sum using millify() and returns a green badge (or grey 'no releases' if none exist).
• Updates documentation and example lists in pages/api/github.ts and public/badges.md.

Implementation Notes & Trade-offs

1. Not 100% of All-Time Downloads for Mega Repos: This solution does not sum 100% of releases for mega repositories with hundreds of releases.
2. Timeout Constraints: While increasing per_page to 100 fetches more releases, heavy repositories with many binary assets per release (like electron/electron) generate large JSON responses that trigger RequestError: Timeout awaiting 'request' for 6400ms configured in libs/got.ts.
3. Pagination Risks: Implementing a full pagination loop to iterate through all release pages until the end was considered, but poses a risk of hitting rate limits and creating excessive request bursts (DDoS-like behavior) on very large repositories.
4. Current Choice (per_page=30): Querying the 30 most recent releases proved to be the safest and most reliable threshold during testing across various repositories.

Suggestions for improvements or alternative strategies are welcome!

Usage

![Total Downloads](https://badgen.net/github/assets-dl/electron/electron/total)

[vercel]

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