chore: finish the Guard-Core org migration (docs, metadata, links)

[rennf93]

Summary

Finishes the rennf93 to Guard-Core org migration for everything this repo owns: docs, metadata, links, and badges. Follows commit d27b973 (#151), which covered the workflow/OIDC side. History entries in CHANGELOG.md and docs/release-notes.md are intentionally untouched.

Categories fixed

• README.md: hero link, logo (raw.githubusercontent), CI/Release/CodeQL badge hrefs and images, Docs nav link, tutorial and API deep links, docs index links, ecosystem and author links. Added a Docs badge (shields.io, same HTML badge block style) linking https://guard-core.github.io/fastapi-guard/latest/
• mkdocs.yml: site_url, repo_name, repo_url, social link, og:image, author url (edit_uri kept as edit/master/docs/)
• pyproject.toml: all four project.urls plus author email moved to rennf93@guard-core.com
• .github/FUNDING.yml: github: Guard-Core (paypal and tidelift lines untouched)
• .github/ISSUE_TEMPLATE/config.yml: docs contact link and discussions link
• .github/scripts/bump_version.py: version bump regex now matches ghcr.io/guard-core/fastapi-guard-example (lowercase, matching the updated docs/index.md)
• SECURITY.md: advisory links and docs link
• CODE_OF_CONDUCT.md: enforcement contact moved to contact@guard-core.com
• context7.json: context7.com/Guard-Core/fastapi-guard
• docs/: index.md (badges, clone URL, orgs/packages URL, ghcr pull paths now ghcr.io/guard-core/fastapi-guard-example), llms.txt (all 52 hits incl. author handle), robots.txt sitemap, api/overview.md, api/core-architecture.md, tutorial pages (telemetry, decorators/overview, examples/example-app, integration)
• AGENTS.md and CLAUDE.md: ecosystem position, boundary rules, related projects (9 hits each)
• guard/.agents/skills/fastapi-guard/SKILL.md: docs link plus related projects (lines 205, 212-218)
• Makefile: sanity-passed every target, no owner or path references (clean)

Known exceptions (intentional, not migration debt)

• .github/workflows/docs.yml (2 hits) and .github/workflows/release.yml (1 hit) keep uses: rennf93/github-actions-secrets-mgmt@v1.5 and rennf93/upsert-context7@1.1. Those action repos do not exist under Guard-Core yet (GitHub API 404), so rewriting would break docs and release CI. chore: Guard-Core org transfer - workflow updates and OIDC publishing #151 left them deliberately for the same reason.
• CHANGELOG.md (6) and docs/release-notes.md (6): history records, left as-is.
• pyproject.toml (1 hit): the remaining string is the new author email rennf93@guard-core.com itself.

Verification

• uv run ruff format --check and uv run ruff check on .github/scripts/bump_version.py: pass (1 file already formatted, All checks passed)
• uv run mypy guard/: 17 errors in 4 files, identical to the pre-change baseline on origin/master (0 new)
• uv run mkdocs build --strict: exit 0, 0 errors, 0 warnings (baseline on origin/master also exit 0, no new errors)
• uv run python -c "import tomllib; tomllib.load(open('pyproject.toml','rb'))": parses (TOML_OK, run on Python 3.12 since the project env is 3.10)
• git grep -n rennf93: 175 lines before, 16 after. The 16: 12 history leftovers (allowed), 3 workflow action refs (exceptions above), 1 = the new author email
• Commit git log -1 --format="%G?" = G (GPG signed)
• Note: .github/workflows/version-update.log was reported as a committed log artifact, but it was never tracked (untracked and covered by the .gitignore *.log rule). Removed from the local working tree; no repo change required.
• Pre-existing quirk noticed, not touched: docs/index.md uses docker run -host 0.0.0.0 (single dash) where gunicorn/docker expect --host.