feat: initial copr-publish composite action

Wraps copr-cli submit/watch/download-build with per-chroot log
dumping as collapsible ::group:: blocks. Moves the logic previously
living at .gitea/scripts/copr-build.sh in helexa/cortex into a
reusable action so every consumer gets live log visibility and
consistent failure diagnostics.

Inputs: project, srpm (glob OK), copr-config (secret).

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

action.yml

@@ -0,0 +1,44 @@
+name: 'Publish to Fedora COPR'
+description: >
+  Submit a source RPM to Fedora COPR, watch the build through to
+  completion, and dump each chroot's builder-live.log into the CI
+  output as collapsible groups.
+author: 'helexa'
+
+branding:
+  icon: package
+  color: blue
+
+inputs:
+  project:
+    description: 'COPR project in the form <owner>/<project> (e.g. helexa/cortex).'
+    required: true
+  srpm:
+    description: >
+      Path(s) to the source RPM(s) to submit. Glob patterns are expanded
+      by the shell, so '*.src.rpm' is fine.
+    required: true
+  copr-config:
+    description: >
+      Contents of ~/.config/copr — obtain from
+      https://copr.fedorainfracloud.org/api/ and pass via secrets.
+    required: true
+
+runs:
+  using: composite
+  steps:
+    - name: Configure copr-cli
+      shell: bash
+      run: |
+        mkdir -p ~/.config
+        umask 077
+        printf '%s\n' "${{ inputs.copr-config }}" > ~/.config/copr
+
+    - name: Submit build and stream logs
+      shell: bash
+      env:
+        COPR_PROJECT: ${{ inputs.project }}
+        COPR_SRPM: ${{ inputs.srpm }}
+      run: |
+        # shellcheck disable=SC2086
+        bash "${{ github.action_path }}/scripts/copr-build.sh" "$COPR_PROJECT" $COPR_SRPM