ci: run MLX contracts on self-hosted runners

Author: apstenku123

.github/workflows/ci-self-hosted.yml

@@ -0,0 +1,62 @@
+name: CppMega MLX self-hosted CI
+
+on:
+  pull_request:
+    branches: [main]
+  push:
+    branches: [main]
+  workflow_dispatch:
+
+concurrency:
+  group: cppmega-mlx-ci-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  mac-contracts:
+    name: macOS MLX data, model, and eval contracts
+    runs-on: [self-hosted, macOS, ARM64, cppmega-mlx-macos]
+    timeout-minutes: 30
+    steps:
+      - uses: actions/checkout@v4
+      - name: Run focused MLX contract suite
+        shell: bash
+        run: |
+          set -euo pipefail
+          python_bin=/Volumes/external/sources/cppmega.mlx/.venv/bin/python
+          test -x "${python_bin}"
+          "${python_bin}" -m pytest -q \
+            tests/test_ast_fim.py \
+            tests/test_audit_sidecar_parquet.py \
+            tests/test_cpp_jsonl_generation_compile_eval.py \
+            tests/test_domain_graph_routes.py \
+            tests/test_eval_domain_routed_codegen.py \
+            tests/test_inference_generation.py \
+            tests/test_megatron_indexed.py \
+            tests/test_pack_enriched_rows.py \
+            tests/test_streaming_conveyor_progress.py \
+            tests/test_process_commits_fail_loud.py \
+            tests/test_repair_packed_document_boundaries.py
+          git diff --check
+
+  linux-portable:
+    name: Linux portable conveyor contracts
+    runs-on: [self-hosted, Linux, X64, cppmega-mlx]
+    timeout-minutes: 20
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: "3.13"
+      - name: Install portable test dependencies
+        run: python -m pip install --disable-pip-version-check pytest numpy pyarrow tokenizers zstandard
+      - name: Run portable script contracts
+        shell: bash
+        run: |
+          set -euo pipefail
+          python -m pytest -q \
+            tests/test_audit_sidecar_parquet.py \
+            tests/test_pack_enriched_rows.py \
+            tests/test_streaming_conveyor_progress.py \
+            tests/test_process_commits_fail_loud.py \
+            tests/test_repair_packed_document_boundaries.py
+          git diff --check