Fix Ollama pull failure propagation and Azure OpenAI vector store readiness

- Ollama CI: fail the step immediately if model pull fails after 3
  retries instead of silently proceeding to tests
- Azure OpenAI file search: add the same vector-store readiness polling
  that was applied to the non-Azure OpenAI tests, preventing eventual
  consistency race conditions

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

.github/workflows/python-integration-tests.yml

@@ -195,13 +195,19 @@ jobs:
           done
           # Pull models with retry for transient 429 rate limits
           for model in qwen2.5:1.5b nomic-embed-text; do
+            pulled=false
             for attempt in 1 2 3; do
               if ollama pull "$model"; then
+                pulled=true
                 break
               fi
               echo "Retry $attempt for $model (waiting 15s)..."
               sleep 15
             done
+            if [ "$pulled" != "true" ]; then
+              echo "ERROR: Failed to pull $model after 3 attempts"
+              exit 1
+            fi
           done
         working-directory: .
       - name: Start local MCP server