Move sample validation script from samples/ to scripts/ (#4400)

python/scripts/sample_validation/__init__.py

@@ -0,0 +1,25 @@
+# Copyright (c) Microsoft. All rights reserved.
+
+"""
+Sample Validation System
+
+A workflow-based system for validating Python samples by:
+1. Discovering all sample files
+2. Creating a dynamic nested concurrent workflow (one GitHub agent per sample)
+3. Running the nested workflow
+4. Generating a validation report
+
+Usage:
+    uv run python -m sample_validation
+    uv run python -m sample_validation --subdir 01-get-started
+"""
+
+from sample_validation.models import Report, RunResult, SampleInfo
+from sample_validation.workflow import create_validation_workflow
+
+__all__ = [
+    "SampleInfo",
+    "RunResult",
+    "Report",
+    "create_validation_workflow",
+]