Replace stale test count with live main CI badge

[tomqwu]

Summary:

• Replace the hard-coded 413 passing badge with live GitHub Actions CI status for main.

Changed files:

• README.md: badge image and link to main CI runs.

Validation:

• Badge URL returns a valid CI status SVG.
• Full local make test-all passed.
• git diff --check passed.

Follow-ups:

• Merge only after CI, AI review and GitHub merge requirements pass.

[github-actions]

AI review (Ollama: glm-5.3-flash)

Head: 572a788
Base: cb1b501

{
  "verdict": "SAFE TO MERGE",
  "summary": "Docs-only change replacing the stale hard-coded '413 passing' shields.io badge with a live GitHub Actions CI badge for the main branch. The badge URL (badge.svg?branch=main) and the link (workflows/ci.yml?query=branch%3Amain) use correct GitHub Actions badge/link syntax, and removing the hard-coded test count eliminates future staleness. No code, dependency, security, or tenant-isolation impact; the only URLs added point to the project's own GitHub repository. No P0/P1 issues found. Two nonblocking P3 notes: (1) GitHub's native workflow badge SVG does not honor the 'style' query parameter, so it will render in the default flat style and look visually inconsistent with the surrounding 'for-the-badge' style badges — an alternative is routing the status through shields.io if visual uniformity matters; (2) this diff-only review cannot confirm that .github/workflows/ci.yml exists with that exact filename — if the workflow file is named differently (e.g., tests.yml), the badge would render 'no status' and the link would 404, so confirm the path matches the actual workflow file. Neither issue blocks merge.",
  "findings": [
    {
      "priority": "P3",
      "path": "README.md",
      "line": 9,
      "detail": "Style inconsistency: the surrounding badges use shields.io with 'style=for-the-badge', but GitHub's native actions badge.svg ignores style parameters and renders flat/small. Fix (optional): use https://img.shields.io/github/actions/workflow/status/tomqwu/SignUpFlow/ci.yml?branch=main&style=for-the-badge to keep visual uniformity, or accept the mixed style."
    },
    {
      "priority": "P3",
      "path": "README.md",
      "line": 9,
      "detail": "Diff-only limitation: cannot verify that .github/workflows/ci.yml exists with this exact filename on main. If the workflow file is named differently, the badge shows 'no status' and the link 404s. Fix: confirm the badge path matches the actual workflow file name before merge."
    }
  ]
}

Diff-only advisory review; CI and GitHub mergeability remain mandatory.