T-109: Rewrite tests router with full Red/Blue workflow endpoints - list with filters, create from template, Red/Blue team updates with state guards, start-execution, submit-red, submit-blue, validate-red, validate-blue, reopen, and timeline. All using workflow service from Phase 11.
T-110: Rewrite evidence router with Red/Blue separation - upload with team field, list with team filter, delete with state-based permissions. Red Team edits in draft/red_executing, Blue Team in blue_evaluating, admin bypasses all.
T-111: Create test_templates router with full CRUD - paginated list with source/platform/severity/search filters, by-technique lookup, admin-only create/update, and soft delete. Registered in main.py.
T-112: Add POST /system/import-atomic-tests endpoint to system router - admin-only trigger for Atomic Red Team import with error handling and statistics response.
Includes validation tests for all four tasks (35 checks total).
