Separate abstractions from implementations following DIP:
servers/ drivers/
│ │
▼ ▼
ports/ (trait-only crates, zero deps)
New crates:
ports/ (abstractions):
- port-framebuffer: Framebuffer trait
- port-block-device: BlockDevice trait + SectorId
- port-input-device: InputDevice trait + InputEvent types
drivers/ (implementations depend on ports/):
- driver-framebuffer-virtio: VirtIO GPU framebuffer
- driver-framebuffer-mock: test double
- driver-block-virtio: VirtIO block device
bins/ (composition roots wire server + driver):
- display-qemu: DisplayServer<VirtioFramebuffer>
- storage-qemu: storage server with VirtIO block
Servers no longer own their hardware traits or driver code.
Neither server nor driver depends on the other — both point
inward to the port abstraction.
