Add workflow for triggering cdb migrations

.github/workflows/migrate_cdb.yaml

@@ -0,0 +1,80 @@
+name: Trigger ConsDB Database Migrations
+
+on:
+  pull_request:
+    types: [closed]
+
+jobs:
+  migrate-cdb:
+    runs-on: ubuntu-latest
+    if: github.event.pull_request.merged == true  # Only trigger on merged PRs
+
+    steps:
+
+      - name: Checkout PR repo
+        uses: actions/checkout@v4
+        with:
+          ref: ${{ github.event.pull_request.merge_commit_sha }}
+          path: pr
+
+      - name: Checkout main repo
+        uses: actions/checkout@v4
+        with:
+          ref: ${{ github.event.pull_request.base.sha }}
+          path: main
+
+      - name: Setup Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+          cache: "pip"
+
+      - name: Install dependencies
+        working-directory: ${{ github.workspace }}/pr
+        run: |
+          set -e
+          python -m pip install --upgrade pip uv
+          uv pip install --system -r requirements.txt
+        shell: bash
+
+      - name: Compare PR to main
+        working-directory: ${{ github.workspace }}/pr
+        run: |
+          CHANGED_FILES=()
+          for SCHEMA_FILE in python/lsst/sdm_schemas/schemas/cdb_*.yaml; do
+            MAIN_FILE=../main/python/lsst/sdm_schemas/schemas/$(basename $SCHEMA_FILE)
+            if [ -f "$MAIN_FILE" ]; then
+              echo "Comparing $MAIN_FILE to $SCHEMA_FILE"
+              DIFF_RESULTS=$(felis diff --comparator alembic $MAIN_FILE $SCHEMA_FILE)
+              if [ $? -ne 0 ]; then
+                echo "Error running felis diff on $SCHEMA_FILE"
+                exit 1
+              fi
+              echo "$DIFF_RESULTS"
+              if [ -n "$DIFF_RESULTS" ]; then
+                echo "Schema file $SCHEMA_FILE has changed"
+                CHANGED_FILES+=($SCHEMA_FILE)
+              fi
+            else
+              echo "Schema file $SCHEMA_FILE is new"
+              CHANGED_FILES+=($SCHEMA_FILE)
+            fi
+          done
+          if [ ${#CHANGED_FILES[@]} -eq 0 ]; then
+            echo "No cdb schema files changed"
+            exit 0
+          else
+            echo "Changed cdb schema files: ${CHANGED_FILES[@]}"
+          fi
+
+      - name: Trigger migration workflow in consdb repository
+        uses: peter-evans/repository-dispatch@v3
+        with:
+          token: ${{ secrets.REPO_DISPATCH_TOKEN }}
+          repository: JeremyMcCormick/consdb-dm-47507
+          event-type: migration
+          client-payload: |
+            {
+              "branch_name": "${{ github.event.pull_request.head.ref }}",
+              "commit_sha": "${{ github.event.pull_request.merge_commit_sha }}"
+            }