restore workflow dispatch

Author: pillo79

.github/workflows/format_check.yml

@@ -14,15 +14,24 @@ on:
     branches:
       - 'main'
 
+  workflow_dispatch:
+
 jobs:
   verify-format:
     runs-on: ubuntu-latest
     steps:
+
       - name: Checkout code
         uses: actions/checkout@v4
         with:
           submodules: false
           persist-credentials: false
+
+      - name: Get first commit SHA
+        id: first-commit
+        if: github.event_name == 'workflow_dispatch'
+        run: echo "sha=$(git rev-list --max-parents=0 HEAD)" >> $GITHUB_OUTPUT
+
       - name: Get changed source files that need format check
         id: changed-files
         uses: tj-actions/changed-files@ed68ef82c095e0d48ec87eccea555d944a631a4c # v46.0.5
@@ -38,9 +47,12 @@ jobs:
             libraries/extras/**
             libraries/ea_malloc/**
           write_output_files: true
+          base_sha: ${{ steps.first-commit.outputs.sha if github.event_name == 'workflow_dispatch' else '' }}
+
       - name: List changed files
         if: steps.changed-files.outputs.any_changed == 'true'
         run: cat .github/outputs/all_changed_files.txt
+
       - name: Run clang-format check
         if: steps.changed-files.outputs.any_changed == 'true'
         uses: pillo79/clang-format-action@05f671e71f0758aba4d3c9dbb0ee81bc5f0137c6