## MODIFIED Requirements

### Requirement: Key Association
The system SHALL only allow project default-key assignment using keys valid for the authenticated owner's project scope.

#### Scenario: Valid default key assignment
- GIVEN a project owner and an eligible SSH key
- WHEN the owner sets the key as default for the project
- THEN the project stores that key reference

#### Scenario: Invalid default key assignment
- GIVEN a project owner
- WHEN the owner attempts to set an ineligible SSH key as project default
- THEN the system responds with validation failure
