fix(gtm): Fix white screen and implement URL persistence v2.6.1

- Fixed TypeError in SessionBrowser by adding defensive checks for the sessions array.
- Implemented mandatory URL persistence: The research URL is now saved in DB, shown in UI, and included in reports.
- Added 'Start New Analysis' button to the session browser for better UX flow.
- Updated documentation to reflect v2.6.1 changes.

gtm_db_manager.py

@@ -104,7 +104,8 @@ def get_all_projects():
                 updated_at,
                 json_extract(data, '$.phases.phase1_result.specs.metadata.model_name') AS productName,
                 json_extract(data, '$.phases.phase1_result.specs.metadata.category') AS productCategory,
-                json_extract(data, '$.phases.phase1_result.specs.metadata.description') AS productDescription
+                json_extract(data, '$.phases.phase1_result.specs.metadata.description') AS productDescription,
+                json_extract(data, '$.phases.phase1_result.specs.metadata.manufacturer_url') AS sourceUrl
             FROM gtm_projects 
             ORDER BY updated_at DESC
         """
@@ -119,6 +120,8 @@ def get_all_projects():
                 project_dict['productCategory'] = "Uncategorized" # Default category
             if project_dict.get('productDescription') is None:
                 project_dict['productDescription'] = "No description available." # Default description
+            if project_dict.get('sourceUrl') is None:
+                project_dict['sourceUrl'] = "No source URL found." # Default URL
             project_list.append(project_dict)
         return project_list
     finally: