ci: add CLA Assistant Lite workflow

Require contributors to sign the @imqueue Contribution Terms on each PR. Signatures stored per-repo (signatures/version1/cla.json) via GITHUB_TOKEN; no external app or PAT required.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: Mikhus

.github/workflows/cla.yml

@@ -0,0 +1,38 @@
+name: CLA Assistant
+
+on:
+  issue_comment:
+    types: [created]
+  pull_request_target:
+    types: [opened, closed, synchronize]
+
+permissions:
+  actions: write
+  contents: write
+  pull-requests: write
+  statuses: write
+
+jobs:
+  cla:
+    runs-on: ubuntu-latest
+    steps:
+      - name: CLA Assistant
+        if: >-
+          (github.event.comment.body == 'recheck' ||
+           github.event.comment.body == 'I have read the CLA Document and I hereby sign the CLA') ||
+          github.event_name == 'pull_request_target'
+        uses: contributor-assistant/github-action@v2.6.1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          path-to-signatures: 'signatures/version1/cla.json'
+          path-to-document: 'https://github.com/imqueue/.github/blob/master/CONTRIBUTION-TERMS.md'
+          branch: 'master'
+          allowlist: 'dependabot[bot],*[bot]'
+          custom-notsigned-prcomment: >-
+            Thank you for your contribution to **@imqueue**. Before this pull
+            request can be merged, please read the
+            [@imqueue Contribution Terms](https://github.com/imqueue/.github/blob/master/CONTRIBUTION-TERMS.md)
+            and sign them by posting the following comment exactly:
+          custom-pr-sign-comment: 'I have read the CLA Document and I hereby sign the CLA'
+          custom-allsigned-prcomment: 'All contributors have signed the @imqueue Contribution Terms. ✅'