Add workflow to regenerate derived files on schema changes

Triggers on push to main when yaml schema files change, and on
manual dispatch. Regenerates Python datamodel, enums, and docs,
then opens a PR with the changes. Closes any previous unclosed
regen PRs before creating a new one.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: dragon-ai-agent

.github/workflows/regen-derived.yaml

@@ -0,0 +1,104 @@
+---
+name: Regenerate derived files
+on:  # yamllint disable-line rule:truthy
+  push:
+    branches: [main]
+    paths:
+      - "src/valuesets/schema/**/*.yaml"
+      - "src/valuesets/schema/*.yaml"
+  workflow_dispatch:
+
+permissions: {}
+
+jobs:
+  regen:
+    runs-on: ubuntu-latest
+
+    permissions:
+      contents: write
+      pull-requests: write
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Install uv
+        uses: astral-sh/setup-uv@v6
+        with:
+          enable-cache: true
+          cache-dependency-glob: "uv.lock"
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.13"
+
+      - name: Install just
+        run: uv tool install rust-just
+
+      - name: Install dependencies
+        run: uv sync --group dev --no-progress
+
+      - name: Regenerate derived files
+        run: |
+          just gen-project
+          just gen-doc
+
+      - name: Check for changes
+        id: changes
+        run: |
+          git add -A
+          if git diff --cached --quiet; then
+            echo "changed=false" >> "$GITHUB_OUTPUT"
+          else
+            echo "changed=true" >> "$GITHUB_OUTPUT"
+          fi
+
+      - name: Close previous regen PRs
+        if: steps.changes.outputs.changed == 'true'
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          gh pr list \
+            --label "automated-regen" \
+            --state open \
+            --json number \
+            --jq '.[].number' \
+          | while read -r pr; do
+              gh pr close "$pr" --comment "Superseded by a newer regeneration run."
+            done
+
+      - name: Create pull request
+        if: steps.changes.outputs.changed == 'true'
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          BRANCH="auto/regen-derived-$(date +%Y%m%d-%H%M%S)"
+          git config user.name "github-actions[bot]"
+          git config user.email "github-actions[bot]@users.noreply.github.com"
+          git checkout -b "$BRANCH"
+          git commit -m "Regenerate derived files from schema changes"
+          git push -u origin "$BRANCH"
+
+          gh label create "automated-regen" \
+            --description "PRs created by the regen-derived workflow" \
+            --color "c5def5" \
+            --force
+
+          gh pr create \
+            --title "Regenerate derived files" \
+            --label "automated-regen" \
+            --body "$(cat <<'EOF'
+          Automated regeneration of derived files after schema changes.
+
+          Updated by running:
+          ```
+          just gen-project
+          just gen-doc
+          ```
+
+          Please review the diffs before merging.
+          EOF
+          )"