feat: import modular SDL challenge portfolios

[Brad-Edwards]

Summary

• Add a raw modular SDL fallback when SDL import expansion fails upstream.
• Import SDL challenge extensions as workbench challenges with evidence requirements.
• Replace topology behavior-spec narration with network segments, hosts, services, actors, and relationships.
• Simplify deeper object views to reduce repeated parent-level context.
• Add a Render blueprint and make the Docker server bind to the platform PORT.

Validation

• uv run pytest — 139 passed
• pre-push hook — passed
• uv run ruff check .
• uv run ruff format --check .
• npm --prefix frontend run build

Closes #33

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
91.6% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud