ci: install uv in PR workflow for PythonUvProvider tests

TC-3855

The PythonUvProvider unit tests require the uv binary to be available,
since the constructor eagerly validates it via Operations.getExecutable().
This follows the same pattern as other providers (cargo, go, gradle).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Assisted-by: Claude Code

Author: a-oren

.github/workflows/pr.yml

@@ -43,6 +43,8 @@ jobs:
         go-version: '1.20.1'
     - name: Install pnpm
       run: npm install -g pnpm
+    - name: Install uv
+      uses: astral-sh/setup-uv@v6
     - name: get Python location
       id: python-location
       run: |