fix(test-orchestrator): prevent SSRF and path traversal vulnerabilities

- Implement URL scheme validation for LLM endpoint connections.
- Mitigate Server-Side Request Forgery (SSRF) by ensuring only 'http' and 'https' schemes are allowed.
- Sanitize report output paths to prevent directory traversal attacks.
- Ensure test reports are saved only within the current working directory.
- Update RAG pipeline documentation to use Mermaid for improved flow diagram rendering.

docs/Chapter_12_Retrieval_Augmented_Generation_RAG_Pipelines.md

@@ -930,7 +930,7 @@ log_entry = {
 
 #### Example Secure Ingestion Flow
 
-```text
+```mermaid
 Document Upload
     ↓
 Malware Scan → REJECT if threats found