fix(ci): add mlx-swift-lm git submodule and checkout submodules in CI

- Create .gitmodules pointing to SharpAI/mlx-swift-lm.git
- Add submodules: recursive to both build.yml and e2e-test.yml checkout steps
- Remove mlx-swift-lm from .gitignore so git tracks the submodule pointer

Author: solderzzc

.github/workflows/build.yml

@@ -11,6 +11,8 @@ jobs:
     runs-on: macos-15
     steps:
       - uses: actions/checkout@v4
+        with:
+          submodules: recursive
 
       - name: Install Metal Toolchain
         run: xcodebuild -downloadComponent MetalToolchain || true

.github/workflows/e2e-test.yml

@@ -17,6 +17,8 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
+        with:
+          submodules: recursive
 
       - name: Cache Swift packages
         uses: actions/cache@v4

.gitignore

@@ -13,7 +13,6 @@ DerivedData/
 # IDE
 .vscode/
 .idea/
-mlx-swift-lm
 
 # Temporary Artifacts & Logs
 *.log

.gitmodules

@@ -0,0 +1,4 @@
+[submodule "mlx-swift-lm"]
+	path = mlx-swift-lm
+	url = https://github.com/SharpAI/mlx-swift-lm.git
+	branch = main