Bound cold public dashboard fan-out within GitHub and Worker quotas

[jskoiz]

Verified against main at 715c52e.

Impact

A cold public visit currently performs a quick request and then a full request. With 24 recently active, uncached repositories and a one-page repository list, the quick request makes 2 GitHub REST calls and the full request makes 76: viewer + repository list, 48 per-repository commit/latest-PR calls, 24 workflow calls, and 2 issue-search calls. That is 78 unauthenticated requests for one page load, above GitHub's 60-requests-per-hour unauthenticated allowance; the 76-call full Worker invocation also exceeds the 50 external-subrequest limit on Workers Free.

The per-repository latest-PR half of the detail fan-out populates RepoSummary.latestPullRequest, but no browser production code reads that field. A public dashboard can therefore exhaust quota or fail at the Worker boundary while paying for data it does not render. Supplying GITHUB_PUBLIC_TOKEN raises GitHub's API allowance but does not remove the Workers Free subrequest ceiling.

References: GitHub REST rate limits, Cloudflare Workers limits.

Concrete code references

• The client always follows the quick request with a full request when no fresh browser cache exists.
• The full loader fans out repository details, workflow runs, searches, and billing in parallel.
• The default scan set is 24 repositories.
• Each in-scope repository requests both its latest commit and latest pull request.
• Workflow history adds one request per scanned repository.
• The unused latest-pull-request field is part of the shared payload contract.

Acceptance criteria

• A cold public quick-plus-full flow at the default scan depth stays at or below 60 GitHub REST requests total.
• No single public Worker invocation requires more than 50 external subrequests under the same 24-active-repository fixture.
• Remove the unused latest-PR fetch and its contract/cache/test surface unless a real rendered consumer is added; do not leave a compatibility alias or parallel payload shape.
• Preserve recent commits, workflow-failure visibility, the global pull-request and issue feeds, bounded scan behavior, and explicit partial-data warnings.
• If the public default scan depth or payload contract changes, update README.md and docs/ARCHITECTURE.md in the same change.

Test expectations

• Add a server regression test that counts every upstream call for a cold public quick request followed by a cold public full request with 24 active repositories, asserting both ceilings above.
• Assert that authenticated local/hosted aggregation still returns its supported data.
• Run npm run test -- --project server, npm run test -- --project web, and npm run check under Node 24.18.0.

Dependencies / order

Land this before the repository-activity cache invalidation issue, because correct invalidation can increase detail refresh traffic and must inherit the reduced request budget.

Non-goals

• Upgrading the Cloudflare account or relying on a higher paid-plan ceiling.
• Shipping any GitHub token to the browser.
• Expanding the dashboard to scan every repository on every request.
• Adding a distributed cache or background queue.