ci: migrate copr publish to reusable action

Replace the in-repo .gitea/scripts/copr-build.sh and per-job
copr-cli configuration with the shared composite action at
https://git.lair.cafe/actions/copr-publish@v1. Behaviour is
identical — submit, watch, dump per-chroot logs — but the logic
now lives in a single place that other projects can consume.

Removes the actions/checkout step from both COPR jobs since the
build script is no longer local to this repo.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.gitea/scripts/copr-build.sh

@@ -1,61 +0,0 @@
-#!/bin/bash
-# Submit an SRPM to COPR, watch the build, and dump per-chroot build logs
-# to stdout so they are captured in CI output.
-#
-# Usage: copr-build.sh <project> <srpm> [srpm...]
-# Example: copr-build.sh helexa/cortex ./cortex-0.1.2-1.fc43.src.rpm
-
-set -o pipefail
-
-PROJECT="$1"
-shift
-
-if [ -z "$PROJECT" ] || [ "$#" -eq 0 ]; then
-  echo "usage: $0 <project> <srpm> [srpm...]" >&2
-  exit 2
-fi
-
-# Submit without waiting; capture the build ID from stdout.
-SUBMIT_OUT=$(copr-cli build --nowait "$PROJECT" "$@")
-echo "$SUBMIT_OUT"
-BUILD_ID=$(echo "$SUBMIT_OUT" | grep -oP 'Created builds: \K[0-9]+' | head -n1)
-
-if [ -z "$BUILD_ID" ]; then
-  echo "error: could not parse build ID from copr-cli output" >&2
-  exit 1
-fi
-
-echo
-echo "Build $BUILD_ID submitted to $PROJECT"
-echo "Follow live: https://copr.fedorainfracloud.org/coprs/build/$BUILD_ID"
-echo
-
-# Watch the build; captures status transitions to stdout. Exit non-zero
-# on build failure, but defer propagating that until after we've fetched
-# logs so the CI output contains diagnostics either way.
-if copr-cli watch-build "$BUILD_ID"; then
-  STATUS=0
-else
-  STATUS=$?
-fi
-
-# Fetch per-chroot results (logs + rpms). Anonymous download — no auth needed.
-mkdir -p copr-logs
-copr-cli download-build --dest copr-logs "$BUILD_ID" || {
-  echo "warning: failed to download build artifacts" >&2
-}
-
-# Dump each chroot's builder-live.log as a collapsible group.
-for chroot_dir in copr-logs/*/; do
-  [ -d "$chroot_dir" ] || continue
-  chroot=$(basename "$chroot_dir")
-  log="${chroot_dir}builder-live.log"
-  if [ -f "$log" ]; then
-    echo
-    echo "::group::${chroot} builder-live.log"
-    cat "$log"
-    echo "::endgroup::"
-  fi
-done
-
-exit "$STATUS"