Add coverage reporting/badges and split CI between Gitea and GitHub (#5)

Merge dotnet+jest coverage via reportgenerator, publish a self-hosted
coverage badge and build-status badges on the readme. Gitea remains the
full pipeline (build/test/docker push/deploy-qa/smoke); GitHub only
builds and tests since it has no registry secrets or qa runner.

Reviewed-on: #5

scripts/ci/publish-coverage-badge.sh

@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+# Commits the coverage badge refreshed by coverage.sh straight back to the
+# branch that triggered this run, so readme.md's relative badges/coverage.svg
+# link stays current. GITHUB_SERVER_URL/GITHUB_REPOSITORY/GITHUB_REF_NAME are
+# default context env vars on both GitHub Actions and Gitea Actions (Gitea's
+# engine is GitHub-Actions-compatible); GITHUB_TOKEN must be passed in
+# explicitly from the workflow (${{ github.token }}) on both platforms.
+set -euo pipefail
+cd "$(dirname "${BASH_SOURCE[0]}")" && source ./lib.sh
+cd "$CI_ROOT"
+
+[[ -n "${GITHUB_TOKEN:-}" ]] || fail "GITHUB_TOKEN env var is required to push the badge commit"
+[[ -n "${GITHUB_SERVER_URL:-}" ]] || fail "GITHUB_SERVER_URL env var is required to push the badge commit"
+[[ -n "${GITHUB_REPOSITORY:-}" ]] || fail "GITHUB_REPOSITORY env var is required to push the badge commit"
+[[ -n "${GITHUB_REF_NAME:-}" ]] || fail "GITHUB_REF_NAME env var is required to push the badge commit"
+
+if git diff --quiet -- badges/coverage.svg; then
+  log "badges/coverage.svg unchanged; nothing to publish"
+  exit 0
+fi
+
+git config user.name "miccheck-ci"
+git config user.email "ci@miccheck.local"
+git add badges/coverage.svg
+git commit -m "chore: refresh coverage badge [skip ci]"
+
+remote_url="${GITHUB_SERVER_URL}/${GITHUB_REPOSITORY}.git"
+git -c http.extraheader="AUTHORIZATION: bearer ${GITHUB_TOKEN}" push "$remote_url" "HEAD:${GITHUB_REF_NAME}"
+
+log "publish-coverage-badge.sh complete"