Rebrand application from Obsidian to Warehouse13

- Update main app title in Angular frontend
- Update FastAPI application title and API endpoints
- Update static HTML index page
- Update all quickstart scripts (bash, PowerShell, batch)
- Update README files (main and frontend)
- Maintain ◆ symbol in headers

All references to "Obsidian" have been replaced with "Warehouse13" throughout the application.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

frontend/README.md

@@ -1,6 +1,6 @@
-# Obsidian Frontend - Angular Application
+# Warehouse13 Frontend - Angular Application
 
-Modern Angular application for the Obsidian Test Artifact Data Lake.
+Modern Angular application for the Warehouse13 Test Artifact Data Lake.
 
 ## Features