chore: import upstream snapshot with attribution

.github/workflows/regression.yml

@@ -0,0 +1,159 @@
+name: regression
+
+permissions:
+  contents: read
+
+# Suppress hyperframes CLI telemetry from HeyGen's own CI runs.
+# External users' CI continues to emit telemetry unless they set this themselves.
+env:
+  HYPERFRAMES_NO_TELEMETRY: "1"
+
+# Graphite can update a branch and its PR base separately for the same head
+# SHA. Keep only the newest expensive regression run for each PR/ref.
+concurrency:
+  group: regression-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
+on:
+  pull_request:
+  push:
+    branches:
+      - main
+
+jobs:
+  changes:
+    name: Detect changes
+    runs-on: ubuntu-latest
+    timeout-minutes: 2
+    outputs:
+      code: ${{ steps.filter.outputs.code }}
+    steps:
+      # Force git-based change detection instead of the pull_request REST API.
+      # The API path can fail the whole workflow on transient listFiles
+      # timeouts before any regression shard even starts.
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+        with:
+          fetch-depth: 0
+      - uses: dorny/paths-filter@fbd0ab8f3e69293af611ebaee6363fc25e6d187d # v4
+        id: filter
+        with:
+          token: ""
+          filters: |
+            code:
+              - "packages/core/**"
+              - "packages/producer/**"
+              - "packages/engine/**"
+              - "Dockerfile*"
+
+  preflight:
+    name: Preflight (lint + format)
+    needs: changes
+    if: needs.changes.outputs.code == 'true'
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    steps:
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+      - uses: ./.github/actions/preflight
+
+  regression-shards:
+    needs: [changes, preflight]
+    if: needs.changes.outputs.code == 'true'
+    runs-on: ubuntu-latest
+    timeout-minutes: 60
+    strategy:
+      fail-fast: true
+      matrix:
+        # Shards are bin-packed by measured per-test duration (LPT heuristic on
+        # CI run 25893372795) so each row carries ~15-16 min of work. When a
+        # new fixture lands, drop it into the currently-lightest shard or
+        # re-balance against fresh `test_suite_summary` timings. Worst-shard
+        # work time was 19.3 min under the old tag-based split (styles-e);
+        # the rebalance brings every shard within ~40s of the others.
+        include:
+          - shard: shard-1
+            args: "hdr-regression style-5-prod style-3-prod mov-prores"
+          - shard: shard-2
+            args: "style-15-prod hdr-hlg-regression style-1-prod many-cuts vfr-screen-recording render-symlinked-assets"
+          - shard: shard-3
+            args: "style-7-prod style-8-prod style-10-prod css-spinner-render-compat webm-transparency mp4-h264-sdr webm-vp9"
+          - shard: shard-4
+            args: "style-16-prod style-9-prod style-17-prod iframe-render-compat variables-prod mp4-h265-sdr"
+          - shard: shard-5
+            args: "style-4-prod style-11-prod style-2-prod animejs-adapter typegpu-adapter parallel-capture-regression"
+          - shard: shard-6
+            args: "overlay-montage-prod style-12-prod chat missing-host-comp-id png-sequence portrait-edge-bleed"
+          - shard: shard-7
+            args: "sub-composition-video style-18-prod raf-ball-render-compat font-variant-numeric sub-comp-t0 sub-comp-id-selector"
+          - shard: shard-8
+            args: "style-13-prod style-6-prod vignelli-stacking gsap-letters-render-compat audio-mux-parity"
+    steps:
+      - name: Checkout (with LFS)
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+        with:
+          lfs: true
+
+      - name: Validate LFS files
+        run: |
+          echo "Checking golden baseline MP4s are real files (not LFS pointers)..."
+          for mp4 in packages/producer/tests/*/output/output.mp4; do
+            if [ -f "$mp4" ]; then
+              size=$(stat --format=%s "$mp4")
+              if [ "$size" -lt 1000 ]; then
+                echo "ERROR: $mp4 appears to be an LFS pointer ($size bytes)"
+                exit 1
+              fi
+              echo "OK: $mp4 ($size bytes)"
+            fi
+          done
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@8d2750c68a42422c14e847fe6c8ac0403b4cbd6f # v3
+
+      - name: Build test Docker image (cached)
+        uses: docker/build-push-action@10e90e3645eae34f1e60eeb005ba3a3d33f178e8 # v6
+        with:
+          context: .
+          file: Dockerfile.test
+          load: true
+          tags: hyperframes-producer:test
+          cache-from: type=gha,scope=regression-test-image
+          # PR matrices can fan out across many stacked branches at once. Let
+          # them consume the shared cache, but keep a single writer on main so
+          # concurrent exports cannot exhaust the Actions cache service.
+          cache-to: ${{ github.event_name == 'push' && 'type=gha,mode=max,scope=regression-test-image' || '' }}
+
+      - name: "Run regression shard: ${{ matrix.shard }}"
+        run: |
+          echo "Shard: ${{ matrix.shard }}"
+          echo "Args: ${{ matrix.args }}"
+          docker run --rm \
+            --security-opt seccomp=unconfined \
+            --shm-size=4g \
+            -v ${{ github.workspace }}/packages/producer/tests:/app/packages/producer/tests \
+            hyperframes-producer:test \
+            ${{ matrix.args }}
+
+      - name: Upload failure artifacts
+        if: failure()
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
+        with:
+          name: regression-failures-${{ matrix.shard }}
+          path: packages/producer/tests/*/failures/
+          if-no-files-found: ignore
+
+  # Summary job — matches the required check name in branch protection
+  regression:
+    runs-on: ubuntu-latest
+    needs: [changes, regression-shards]
+    if: always()
+    steps:
+      - name: Check results
+        run: |
+          if [ "${{ needs.changes.outputs.code }}" != "true" ]; then
+            echo "No code changes — skipping regression (auto-pass)"
+            exit 0
+          fi
+          if [ "${{ needs.regression-shards.result }}" != "success" ]; then
+            echo "One or more regression shards failed"
+            exit 1
+          fi