feat: migrate to Talos v1.12 multi-document config format

[lexfrei]

Summary

Talos v1.12 introduces a new multi-document configuration format that deprecates several v1alpha1 fields. talm should be updated to generate configs in the new format.

Breaking changes in Talos v1.12

Based on Talos v1.12 release notes:

Network configuration

• .machine.network moved to separate documents:
  • HostnameConfig
  • LinkConfig
  • EthernetConfig
  • BondConfig
  • VLANConfig
  • BridgeConfig
  • RouteConfig

Registry configuration

• .machine.registries (v1alpha1) deprecated
• New documents:
  • RegistryMirrorConfig
  • RegistryAuthConfig
  • RegistryTLSConfig

Other changes

• API server uses stricter CIS-aligned TLS cipher suites by default
• LUKS2 volumes use standardized /dev/mapper/luks2-<volume-id> naming
• Kubernetes component images must have explicit tags

Tasks

• Update charts/talm/templates/_helpers.tpl to generate new config documents
• Update charts/cozystack/templates/_helpers.tpl
• Update charts/generic/templates/_helpers.tpl
• Add tests for new config format generation
• Update documentation

References

• PR chore(deps): update dependencies and cleanup forks #98 (dependency update to Talos v1.12.1)
• Talos v1.12 What's New