Integrate dark theme styling from main branch with Angular Material

- Apply dark blue color scheme (#0f172a, #1e293b, #334155) throughout UI
- Update header with blue gradient and Obsidian branding
- Add missing toolbar buttons: Auto-refresh, Seed Data, Search filter
- Implement action buttons (Download, Delete) in artifacts table
- Add client-side search/filtering functionality
- Update app to support sim_source_id field in database
- Move quickstart scripts to repository root for easier access
- Apply dark theme to tables, tabs, and all Material components

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

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

app/models/artifact.py

@@ -20,6 +20,7 @@ class Artifact(Base):
     test_suite = Column(String(500), index=True)
     test_config = Column(JSON)
     test_result = Column(String(50), index=True)  # pass, fail, skip, error
+    sim_source_id = Column(String(500), index=True)  # SIM source identifier for grouping
 
     # Additional metadata
     custom_metadata = Column(JSON)