Add spec.bookings field with typed resource claim entries

[PhilippMatthes]

The Cortex Placement Shim needs to record which resources each instance consumes on a hypervisor, and which capacity is held back from scheduling. Today, the Hypervisor CRD tracks actual resource usage via status.allocation (auto-discovered by kvm-node-agent from libvirt), but has no representation of what Nova thinks is allocated. This prevents the shim from serving allocation and inventory endpoints directly from the CRD.

This PR introduces spec.bookings — the CRD's record of all resource claims as seen by the Placement API. There are two kinds of resource claims:

• Consumers — instance allocations. Each consumer (identified by UUID) holds resources on one or more providers. A consumer can span multiple Hypervisor CRs during live migration.
• Reservations — capacity held back from scheduling. Nova's reserved_host_memory_mb, reserved_host_cpus, and reserved_host_disk_mb config options subtract from available inventory.

The field follows the same field-presence union pattern established by spec.groups (and PodSpec.volumes in core Kubernetes). Each entry populates exactly one type-specific sub-field, and the populated field identifies the booking type:

spec:
  bookings:
    - consumer:
        uuid: "instance-uuid-1"
        resources:
          cpu: "2"
          memory: "4Gi"
        consumerGeneration: 1
        consumerType: "INSTANCE"
        projectID: "proj-123"
        userID: "user-456"
    - reservation:
        name: "nova-reserved"
        resources:
          cpu: "2"
          memory: "512Mi"

A CEL validation rule enforces that exactly one sub-field is populated per entry. The consumerType field is a free-form string to accommodate all consumer types in the Placement API (see API reference).

Library helper functions (GetConsumers, GetConsumer, HasConsumer, GetReservations, GetReservation, SumResources) follow the same pattern as the spec.groups helpers and are reusable across the shim, operator, and scheduler.

The design is extensible: adding a new booking concept means adding one optional pointer field to the Booking struct and a corresponding type-specific struct. No changes to existing fields or consumers are required.

See: cobaltcore-dev/cortex#787

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[github-actions]

Merging this branch will not change overall coverage

Impacted Packages	Coverage Δ	🤖
github.com/cobaltcore-dev/openstack-hypervisor-operator/api/v1	0.00% (ø)
github.com/cobaltcore-dev/openstack-hypervisor-operator/applyconfigurations	0.00% (ø)
github.com/cobaltcore-dev/openstack-hypervisor-operator/applyconfigurations/api/v1	0.00% (ø)

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Coverage by file

Changed files (no unit tests)

Changed File	Coverage Δ	Total	Covered	Missed	🤖
github.com/cobaltcore-dev/openstack-hypervisor-operator/api/v1/hypervisor_types.go	0.00% (ø)	0	0	0
github.com/cobaltcore-dev/openstack-hypervisor-operator/api/v1/zz_generated.deepcopy.go	0.00% (ø)	0	0	0
github.com/cobaltcore-dev/openstack-hypervisor-operator/applyconfigurations/api/v1/booking.go	0.00% (ø)	0	0	0
github.com/cobaltcore-dev/openstack-hypervisor-operator/applyconfigurations/api/v1/consumerbooking.go	0.00% (ø)	0	0	0
github.com/cobaltcore-dev/openstack-hypervisor-operator/applyconfigurations/api/v1/hypervisorspec.go	0.00% (ø)	0	0	0
github.com/cobaltcore-dev/openstack-hypervisor-operator/applyconfigurations/api/v1/reservationbooking.go	0.00% (ø)	0	0	0
github.com/cobaltcore-dev/openstack-hypervisor-operator/applyconfigurations/utils.go	0.00% (ø)	0	0	0

Please note that the "Total", "Covered", and "Missed" counts above refer to code statements instead of lines of code. The value in brackets refers to the test coverage of that file in the old version of the code.

Changed unit test files

• github.com/cobaltcore-dev/openstack-hypervisor-operator/api/v1/hypervisor_validation_test.go