fix(hygiene): remove committed conflict markers from 78 files + add CI gate

.github/workflows/lint-and-format.yml

@@ -537,6 +537,42 @@ jobs:
       - name: Build docs (strict — fail on any warning)
         run: mkdocs build --strict
 
+  check-conflict-markers:
+    if: github.event_name != 'pull_request' || github.event.pull_request.draft == false
+    # Fast, pre-commit-independent gate that fails immediately if git conflict
+    # markers (<<<<<<< / ======= / >>>>>>>) are found committed in any text
+    # file. This is intentionally redundant with pre-commit's check-merge-conflict
+    # hook — the hook only fires on local `git commit`, whereas this step fires
+    # on every push and PR, catching markers that sneak in via direct pushes,
+    # GitHub UI merges, or --no-verify bypasses.
+    # Excludes: binary extensions, LICENSES/ vendored texts, and the
+    # .pre-commit-config.yaml itself (which references hook IDs that contain
+    # the string "conflict").
+    name: Check — No committed conflict markers
+    runs-on: ubuntu-latest
+    timeout-minutes: 2
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd  # v6.0.2
+      - name: Fail if conflict markers are committed
+        run: |
+          set +e
+          hits=$(git grep -In --untracked=false \
+            -e '^<<<<<<< ' -e '^=======$' -e '^>>>>>>> ' \
+            -- \
+            ':(exclude)LICENSES/**' \
+            ':(exclude)*.yuv' ':(exclude)*.pkl' ':(exclude)*.onnx' \
+            ':(exclude)*.bin' ':(exclude)*.mexa64' ':(exclude)*.mexw64' \
+            ':(exclude)*.mexmaci64' ':(exclude)*.npy' \
+            ':(exclude)*.so' ':(exclude)*.a' ':(exclude)*.dylib' \
+            ':(exclude)*.dll' ':(exclude)*.onnx.data' \
+            2>/dev/null)
+          if [ -n "$hits" ]; then
+            echo "::error::Committed conflict markers found — resolve before merging:"
+            echo "$hits"
+            exit 1
+          fi
+          echo "No conflict markers found."
+
   shellcheck:
     if: github.event_name != 'pull_request' || github.event.pull_request.draft == false
     # T7-CI-DEDUP — body collapsed to a no-op proxy that depends on the

changelog.d/fixed/conflict-marker-sweep-plus-ci-gate.md

@@ -0,0 +1,12 @@
+### Fixed
+
+- Remove committed conflict markers from 78 files introduced by the
+  post-merge-train sweep commit (24bb5daf89). Markers kept the HEAD side
+  in every case — the pre-ADR-0700-correct `core/` path references plus
+  any forward-looking code additions (math import, `_sanitize_nonfinite`,
+  `float_ansnr` removal note in test_hip_smoke.c, C++23 safety invariants
+  in core/AGENTS.md).
+- Add `check-conflict-markers` CI job to `lint-and-format.yml`: a fast,
+  pre-commit-independent `git grep` gate that fails immediately on any
+  committed conflict marker (`<<<<<<< ` / `=======` / `>>>>>>> `),
+  blocking merges that bypass the local pre-commit hook.

core/src/feature/cuda/integer_vif_cuda.c

@@ -346,9 +346,8 @@ int filter1d_8(VifStateCuda *s, VifBufferCuda *buf, uint8_t *ref_in, uint8_t *di
          * ADR-0743: __launch_bounds__(128, 10) on filter1d_8_horizontal_kernel_2_17_9
          * reduced registers from 56 to 48.  vpt=2 is retained (vpt=4 evaluated and
          * rejected — smem-limited at 37.5% occupancy vs 62.5% for vpt=2).
-<<<<<<< HEAD
-         */        const int BLOCKX = 128, BLOCKY = 1, val_per_thread = 2;        const int BLOCKX = 128, BLOCKY = 1, val_per_thread = 2;
->>>>>>> refactor(core): rename feature_extractor.c → .cpp (ADR-0772)
+         */
+        const int BLOCKX = 128, BLOCKY = 1, val_per_thread = 2;
 
         void *args_hori[] = {
             &*buf, &w, &h, (uint16_t *)&vif_filter1d_table, &vif_enhn_gain_limit, &buf->accum};