Add 'overlay' to _VALID_STRATEGIES frozenset in ResourceTypeConfigSchema
validator so that resource type YAML configs specifying
sandbox_strategy: overlay are accepted without raising ValueError.
The overlay strategy is defined in the specification for fs-mount
resources using OverlayFS. The domain model SandboxStrategy enum
correctly includes OVERLAY = 'overlay', but the YAML schema validator
in src/cleveragents/resource/schema.py was missing it from
_VALID_STRATEGIES, causing a validation error on valid configurations.
Changes:
- Add 'overlay' to _VALID_STRATEGIES in src/cleveragents/resource/schema.py
- Add BDD scenario: 'Schema accepts overlay sandbox strategy'
- Add step definitions for the new scenario
ISSUES CLOSED: #2827
freemo