docs (talos hvm): add the Talos Hypervisor docs

[Iheanacho-ai]

What

Adds the Talos Hypervisor docs section: navigation, overview, getting started (requirements, install a hypervisor host, run your first virtual machine), storage (content libraries and images, storage pools), and virtual machines (configuration, consoles). Also bumps Omni to v1.12.4 and regenerates the Talos v1.15 reference for v1.15.0-alpha.1.

Why

Talos Hypervisor ships with Talos Linux v1.15.0-alpha.1 for TalosCon. The pages link to each other and to the v1.15 configuration reference, so the broken-links check fails when they are merged separately. This PR combines them so they merge together.

Supersedes

• docs (talos hvm): add the Talos Hypervisor navigation structure #805: navigation structure
• docs (talos hvm): add the What Is Talos Hypervisor overview page #806: What Is Talos Hypervisor overview
• docs (talos hvm): add the requirements and run your first virtual mac… #807: requirements, install a hypervisor host, and run your first virtual machine
• docs (talos hvm): add the Storage pages for Talos Hypervisor #808: storage pages
• docs (talos hvm): add the Virtual Machines pages for Talos Hypervisor #809: virtual machine pages
• docs: bump Omni to v1.12.4 and Talos v1.15 to alpha.1 #865: Omni v1.12.4 and Talos v1.15.0-alpha.1 reference

Each PR's commit is included unchanged, and review comments from #806–#809 are already addressed in them.

Change

• hypervisor.yaml and the generated docs.json: new Talos Hypervisor tab.
• public/hypervisor/: eight new pages.
• public/talos/v1.15/reference/: regenerated for v1.15.0-alpha.1, including the ContentLibraryConfig, VirtualMachineConfig, and StoragePool pages.
• Omni reference and version variables updated to v1.12.4.

Testing

• Ran: every procedure on the Install, Run your first virtual machine, Upload and manage images, Create a storage pool, Configure a virtual machine, and Access the virtual machine console pages, including serial and VNC consoles and cloud-init.
• Where: a ThinkPad (amd64) hypervisor host on a v1.15.0-alpha.0 development build with the libvirtd extension.
• By: by hand, and with an agent.
• Result: all steps passed. Claims were also checked against the v1.15.0-alpha.1 source.
• Not tested on a host: Image Factory image build (Step 1 of Install, now works for alpha.1), worker hosts, cloud hosts, arm64, and writable disks in storage pools (new in alpha.1, documented from source).
• Checks run locally: make docs.json (no diff), validate-docs-nav, canonical-links-check, check-frontmatter-changed, and style-check-changed all pass, and every link from the hypervisor pages resolves.

[sterlingkoch]

/m