fix(ci): remove --system flag from uv pip install commands

The --system flag causes uv to install packages into the system Python
instead of the virtual environment created by 'uv sync'. This was
causing CI failures because:
1. setup-python action runs 'uv sync' creating .venv/
2. protobuf/kfp-k8s actions used 'uv pip install --system' installing
   to system Python, not the venv
3. 'uv run pytest' runs in .venv/ which lacked those packages

Changes:
- Remove redundant uv setup from protobuf and kfp-k8s actions (now
  provided by setup-python action)
- Remove --system flag from all uv pip install commands
- Update kfp-kubernetes-native-migration-tests workflow to use our
  setup-python action and uv commands

Signed-off-by: sh4shv4t <shashvat.k.singh.16@gmail.com>

Author: sh4shv4t

.github/actions/kfp-k8s/action.yml

@@ -12,12 +12,6 @@ inputs:
 runs:
   using: "composite"
   steps:
-    - name: Setup uv
-      shell: bash
-      run: |
-        curl -LsSf https://astral.sh/uv/install.sh | sh
-        echo "$HOME/.local/bin" >> $GITHUB_PATH
-
     - name: Build & install kfp-server-api dist
       id: install-kfp-server-api
       shell: bash
@@ -30,7 +24,7 @@ runs:
           echo "Error: No wheel file found"
           exit 1
         fi
-        uv pip install --system "$wheel_file"
+        uv pip install "$wheel_file"
 
     - name: Build kfp dist
       id: install-kfp
@@ -44,7 +38,7 @@ runs:
           echo "Error: No wheel file found"
           exit 1
         fi
-        uv pip install --system "$wheel_file"
+        uv pip install "$wheel_file"
 
     - name: Generate kfp-kubernetes python proto files from source
       id: generate-kfp-kubernetes-proto-files
@@ -68,7 +62,7 @@ runs:
       shell: bash
       if: ${{ steps.generate-kfp-kubernetes-proto-files.outcome == 'success' }}
       run: |
-        uv pip install --system -e ./kubernetes_platform/python[dev] --find-links=sdk/python/dist
+        uv pip install -e ./kubernetes_platform/python[dev] --find-links=sdk/python/dist
 
     # testing reinstalling kfp package from source with no deps
     - name: Reinstall kfp from source with no deps
@@ -77,4 +71,4 @@ runs:
       if: ${{ steps.install-kfp-kubernetes.outcome == 'success' }}
       working-directory: ./sdk/python
       run: |
-        uv pip install --system . -I --no-deps
+        uv pip install . -I --no-deps

.github/actions/protobuf/action.yml

@@ -38,16 +38,10 @@ runs:
         rm $PROTOC_ZIP
         protoc --version
 
-    - name: Setup uv
-      shell: bash
-      run: |
-        curl -LsSf https://astral.sh/uv/install.sh | sh
-        echo "$HOME/.local/bin" >> $GITHUB_PATH
-
     - name: Install protobuf dependencies with uv
       shell: bash
       run: |
-        uv pip install --system setuptools==${{inputs.setuptools_version}} wheel==${{inputs.wheels_version}} protobuf==${{inputs.protobuf_python_version}}
+        uv pip install setuptools==${{inputs.setuptools_version}} wheel==${{inputs.wheels_version}} protobuf==${{inputs.protobuf_python_version}}
 
     - name: Generate API proto files
       working-directory: ./api
@@ -62,7 +56,7 @@ runs:
           echo "Error: No wheel files found in api/v2alpha1/python/dist/"
           exit 1
         fi
-        uv pip install --system "$wheel_file"
+        uv pip install "$wheel_file"
 
     - name: Generate kfp-pipeline-spec golang files
       if: ${{ inputs.generate_golang_proto == 'true' }}

.github/workflows/kfp-kubernetes-native-migration-tests.yaml

@@ -32,11 +32,10 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v5
 
-      - name: Set up Python
-        uses: actions/setup-python@v6
+      - name: Setup Python with uv
+        uses: ./.github/actions/setup-python
         with:
           python-version: "3.9"
-          cache: 'pip'
 
       - name: Create KFP cluster
         id: create-kfp-cluster
@@ -67,12 +66,12 @@ jobs:
       - name: Install requirements
         id: install-requirements
         if: ${{ steps.install-kfp-k8s-deps.outcome == 'success' }}
-        run: pip install -r ./test/kfp-kubernetes-native-migration-tests/requirements.txt
+        run: uv pip install -r ./test/kfp-kubernetes-native-migration-tests/requirements.txt
 
       - name: Create test pipelines in DB mode
         if: ${{ steps.install-requirements.outcome == 'success' }}
         id: create-test-pipelines
-        run: python ./test/kfp-kubernetes-native-migration-tests/create_test_pipelines.py
+        run: uv run python ./test/kfp-kubernetes-native-migration-tests/create_test_pipelines.py
         continue-on-error: true
 
       - name: Run DB mode migration tests
@@ -82,7 +81,7 @@ jobs:
           PULL_NUMBER: ${{ github.event.pull_request.number }}
           REPO_NAME: ${{ github.repository }}
           KFP_ENDPOINT: "http://localhost:8888"
-        run: python -m pytest ./test/kfp-kubernetes-native-migration-tests/kfp_db_mode_migration_tests.py -v
+        run: uv run pytest ./test/kfp-kubernetes-native-migration-tests/kfp_db_mode_migration_tests.py -v
         continue-on-error: true
 
       - name: Install cert-manager
@@ -165,7 +164,7 @@ jobs:
           PULL_NUMBER: ${{ github.event.pull_request.number }}
           REPO_NAME: ${{ github.repository }}
           KFP_ENDPOINT: "http://localhost:8888"
-        run: python -m pytest ./test/kfp-kubernetes-native-migration-tests/kfp_k8s_mode_migration_tests.py -v
+        run: uv run pytest ./test/kfp-kubernetes-native-migration-tests/kfp_k8s_mode_migration_tests.py -v
         continue-on-error: true
 
       - name: Collect failed logs