feat: add validator action

.github/workflows/validate.yml

@@ -0,0 +1,55 @@
+name: Validator Bot
+
+on:
+  pull_request:
+    branches:
+    - master
+    - main
+
+jobs:
+  run-validation:
+    name: Run validation
+    runs-on: self-hosted
+    steps:
+    - uses: lkstrp/pypsa-validator@main
+      with:
+        step: run-self-hosted-validation
+        env_file: environment.yaml
+        snakemake_config: config/config.yaml
+        pre_command: "-call build_scenarios -f"
+
+  upload-artifacts:
+    name: Upload artifacts
+    needs: run-validation
+    runs-on: self-hosted
+    strategy:
+      matrix:
+        include:
+          - {artifact_name: "results (feature branch)", path: "~/pypsa-ariadne/feature/results"}
+          - {artifact_name: "results (base branch)", path: "~/pypsa-ariadne/main/results"}
+          - {artifact_name: "validator-metadata", path: "~/pypsa-ariadne/validator-metadata.yml"}
+    steps:
+    - name: Upload artifacts - ${{ matrix.artifact_name }}
+      uses: actions/upload-artifact@v4
+      with:
+        name: ${{ matrix.artifact_name }}
+        path: |
+            ${{ matrix.path }}
+        if-no-files-found: error
+        retention-days: 90
+
+  comment-on-pr:
+    name: Comment on pull request
+    needs: upload-artifacts
+    runs-on: ubuntu-latest
+    steps:
+      - uses: lkstrp/pypsa-validator@main
+        with:
+          step: create-comment
+          plots: >
+            "
+            /biomass_industry/KN2045_Bal_v4/ariadne/capacity.png
+            /biomass_industry/KN2045_Bal_v4/ariadne/final_energy.png
+            /biomass_industry/KN2045_Bal_v4/ariadne/policy_carbon.png
+            "
+          repo_private_key: ${{ secrets.REPO_PLOTS_PRIVATE_KEY }}