ci : reduce self-hosted server workflow jobs (#24012)

Reduce the number of parallel jobs in server-self-hosted.yml by stacking
test configurations as sequential steps within a single job, following the
pattern from #23927.

- server-metal: 4 matrix jobs -> 1 job with 4 sequential test steps
- server-cuda: 2 matrix jobs -> 1 job with 2 sequential test steps
- server-kleidiai: removed unnecessary single-entry matrix
- removed unused Setup Node.js step from server-metal

Total: 7 parallel jobs -> 3 parallel jobs

Assisted-by: llama.cpp:local pi

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

@@ -42,23 +42,6 @@ jobs:
   server-metal:
     runs-on: [self-hosted, llama-server, macOS, ARM64]
 
-    name: server-metal (${{ matrix.wf_name }})
-    strategy:
-      matrix:
-        build_type: [Release]
-        wf_name: ["GPUx1"]
-        include:
-          - build_type: Release
-            extra_args: "LLAMA_ARG_BACKEND_SAMPLING=1"
-            wf_name:    "GPUx1, backend-sampling"
-          - build_type: Release
-            extra_args: "GGML_METAL_DEVICES=2"
-            wf_name:    "GPUx2"
-          - build_type: Release
-            extra_args: "GGML_METAL_DEVICES=2 LLAMA_ARG_BACKEND_SAMPLING=1"
-            wf_name:    "GPUx2, backend-sampling"
-      fail-fast: false
-
     steps:
       - name: Clone
         id: checkout
@@ -67,44 +50,58 @@ jobs:
           fetch-depth: 0
           ref: ${{ github.event.inputs.sha || github.event.pull_request.head.sha || github.sha || github.head_ref || github.ref_name }}
 
-      - name: Setup Node.js
-        uses: actions/setup-node@v6
-        with:
-          node-version: "24"
-          cache: "npm"
-          cache-dependency-path: "tools/ui/package-lock.json"
-
       - name: Build
         id: cmake_build
         run: |
           cmake -B build -DGGML_SCHED_NO_REALLOC=ON
-          cmake --build build --config ${{ matrix.build_type }} -j $(sysctl -n hw.logicalcpu) --target llama-server
+          cmake --build build --config Release -j $(sysctl -n hw.logicalcpu) --target llama-server
 
-      - name: Tests
+      - name: Python setup
-        id: server_integration_tests
+        id: setup_python
-        if: ${{ (!matrix.disabled_on_pr || !github.event.pull_request) }}
         run: |
           cd tools/server/tests
           python3 -m venv venv
           source venv/bin/activate
           pip install -r requirements.txt
-          export ${{ matrix.extra_args }}
+
+      - name: Tests (GPUx1)
+        id: server_integration_tests
+        if: ${{ !github.event.pull_request }}
+        run: |
+          cd tools/server/tests
+          source venv/bin/activate
+          pytest -v -x -m "not slow"
+
+      - name: Tests (GPUx1, backend-sampling)
+        id: server_integration_tests_backend_sampling
+        if: ${{ !github.event.pull_request }}
+        run: |
+          cd tools/server/tests
+          source venv/bin/activate
+          export LLAMA_ARG_BACKEND_SAMPLING=1
+          pytest -v -x -m "not slow"
+
+      - name: Tests (GPUx2)
+        id: server_integration_tests_gpu2
+        if: ${{ !github.event.pull_request }}
+        run: |
+          cd tools/server/tests
+          source venv/bin/activate
+          export GGML_METAL_DEVICES=2
+          pytest -v -x -m "not slow"
+
+      - name: Tests (GPUx2, backend-sampling)
+        id: server_integration_tests_gpu2_backend_sampling
+        if: ${{ !github.event.pull_request }}
+        run: |
+          cd tools/server/tests
+          source venv/bin/activate
+          export GGML_METAL_DEVICES=2 LLAMA_ARG_BACKEND_SAMPLING=1
           pytest -v -x -m "not slow"
 
   server-cuda:
     runs-on: [self-hosted, llama-server, Linux, NVIDIA]
 
-    name: server-cuda (${{ matrix.wf_name }})
-    strategy:
-      matrix:
-        build_type: [Release]
-        wf_name: ["GPUx1"]
-        include:
-          - build_type: Release
-            extra_args: "LLAMA_ARG_BACKEND_SAMPLING=1"
-            wf_name:    "GPUx1, backend-sampling"
-      fail-fast: false
-
     steps:
       - name: Clone
         id: checkout
@@ -117,32 +114,36 @@ jobs:
         id: cmake_build
         run: |
           cmake -B build -DGGML_CUDA=ON -DGGML_SCHED_NO_REALLOC=ON
-          cmake --build build --config ${{ matrix.build_type }} -j $(nproc) --target llama-server
+          cmake --build build --config Release -j $(nproc) --target llama-server
 
-      - name: Tests
+      - name: Python setup
-        id: server_integration_tests
+        id: setup_python
-        if: ${{ (!matrix.disabled_on_pr || !github.event.pull_request) }}
         run: |
           cd tools/server/tests
           python3 -m venv venv
           source venv/bin/activate
           pip install -r requirements.txt
-          export ${{ matrix.extra_args }}
+
+      - name: Tests (GPUx1)
+        id: server_integration_tests
+        if: ${{ !github.event.pull_request }}
+        run: |
+          cd tools/server/tests
+          source venv/bin/activate
+          pytest -v -x -m "not slow"
+
+      - name: Tests (GPUx1, backend-sampling)
+        id: server_integration_tests_backend_sampling
+        if: ${{ !github.event.pull_request }}
+        run: |
+          cd tools/server/tests
+          source venv/bin/activate
+          export LLAMA_ARG_BACKEND_SAMPLING=1
           pytest -v -x -m "not slow"
 
   server-kleidiai:
     runs-on: ah-ubuntu_22_04-c8g_8x
 
-    name: server-kleidiai (${{ matrix.wf_name }})
-    strategy:
-      matrix:
-        include:
-          - build_type: Release
-            extra_build_flags: "-DGGML_CPU_KLEIDIAI=ON"
-            extra_args: ""
-            wf_name:    "CPUx1, kleidiai"
-      fail-fast: false
-
     steps:
       - name: Clone
         id: checkout
@@ -181,16 +182,21 @@ jobs:
       - name: Build
         id: cmake_build
         run: |
-          cmake -B build -DGGML_SCHED_NO_REALLOC=ON ${{ matrix.extra_build_flags }}
+          cmake -B build -DGGML_SCHED_NO_REALLOC=ON -DGGML_CPU_KLEIDIAI=ON
-          cmake --build build --config ${{ matrix.build_type }} -j $(nproc) --target llama-server
+          cmake --build build --config Release -j $(nproc) --target llama-server
 
-      - name: Tests
+      - name: Python setup
-        id: server_integration_tests
+        id: setup_python
-        if: ${{ (!matrix.disabled_on_pr || !github.event.pull_request) }}
         run: |
           cd tools/server/tests
           python3 -m venv venv
           source venv/bin/activate
           pip install -r requirements.txt
-          export ${{ matrix.extra_args }}
+
+      - name: Tests
+        id: server_integration_tests
+        if: ${{ !github.event.pull_request }}
+        run: |
+          cd tools/server/tests
+          source venv/bin/activate
           pytest -v -x -m "not slow"