CORE-127: enforce scalafmt in github actions

.git-blame-ignore-revs

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+# .git-blame-ignore-revs
+
+# scalafmt mass change
+3487e7a60194a66886572c899a6a93d7355dc376

.github/workflows/format.yaml

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+name: Check formatting for modified files with scalafmt
+
+on:
+  pull_request:
+    paths-ignore: ['**.md']
+
+jobs:
+  format:
+
+    runs-on: ubuntu-latest
+
+    steps:
+
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 2
+          ref: ${{ github.event.pull_request.head.sha }}
+
+      - name: Set up JDK 17
+        uses: actions/setup-java@v4
+        with:
+          distribution: 'temurin'
+          java-version: 17
+          cache: sbt
+
+      - name: Check formatting for modified files
+        run: |
+          sbt scalafmtCheckAll