ci: Add LFS configuration and GitLab SSH to squash & merge script (#725)

Integrate GitLab LFS handling by configuring LFS URLs and enabling SSH setup. This includes adding public GitLab keys and updating the workflow to support secure connections for LFS operations. Ensures proper handling of large files and seamless integration with GitLab.

.github/workflows/sunnypilot-master-dev-c3-prep.yaml

@@ -4,6 +4,8 @@ env:
   DEFAULT_SOURCE_BRANCH: "master-new"
   DEFAULT_TARGET_BRANCH: "nightly"
   PR_LABEL: "dev-c3"
+  LFS_URL: 'https://gitlab.com/sunnypilot/public/sunnypilot-new-lfs.git/info/lfs'
+  LFS_PUSH_URL: 'ssh://git@gitlab.com/sunnypilot/public/sunnypilot-new-lfs.git'
 
 on:
   workflow_dispatch:
@@ -34,6 +36,15 @@ jobs:
         run: |
           git config --global user.name 'github-actions[bot]'
           git config --global user.email 'github-actions[bot]@users.noreply.github.com'
+          
+      - name: Set up SSH
+        uses: webfactory/ssh-agent@v0.9.0
+        with:
+          ssh-private-key: ${{ secrets.SSH_PRIVATE_KEY }}
+
+      - name: Add GitLab public keys
+        run: |
+          ssh-keyscan -H gitlab.com >> ~/.ssh/known_hosts
 
       - name: Set up Python
         uses: actions/setup-python@v5
@@ -113,6 +124,13 @@ jobs:
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 
+      - name: Update LFS Config
+        run: |
+          echo '[lfs]' > .lfsconfig
+          echo '    url = ${{ env.LFS_URL }}' >> .lfsconfig
+          echo '    pushurl = ${{ env.LFS_PUSH_URL }}' >> .lfsconfig
+          echo '    locksverify = false' >> .lfsconfig
+
       - name: Push changes if there are diffs
         id: push-changes  # Add an id so we can reference this step
         run: |