feat(container-registry): add container registry repository and tag commands

Summary

This MR introduces a new container-registry command (alias registry), for listing, viewing, and deleting container registry repositories and tags.

What does this MR do?

Adds support to interact with the GitLab Container Registry via glab.

• Adds glab container-registry repository commands:
  • list
  • view
  • delete
• Adds glab container-registry tag commands:
  • list
  • view
  • delete
  • delete-tags
• Supports project-level repository listing with pagination, tag counts, optional embedded tags, JSON output
• Supports group-level repository listing
• Supports tag listing and detailed lookup
• Support tag deletion (single tag and multiple tag, as offered by the Container Registry API)
• Adds documentation for the new commands
• Includes unit tests

Related Issues

Resolves #8314 (closed)

How has this been tested?

Included unit tests for all commands added and ran various automated checks:

go test ./internal/commands/container_registry/...
make lint
make gen-docs

Manual testing was performed against a GitLab Self-Managed instance with real container registry repositories and tags. The following flows were verified:

• project and group repository listing + deletion
• JSON output with --include-tags and --include-tag-details
• tag listing with and without --details
• single tag deletion
• multi-tag deletion

Usage examples

List container registry repositories for a specific project:

glab container-registry repository list -R gitlab-org/cli

View a single container registry repository, including tags:

glab container-registry repository view <repo-id> --include-tags

List tags for a specific repository with detailed metadata:

glab container-registry tag list <repo-id> --details

View a single tag:

glab container-registry tag view <repo-id> latest

Delete a single tag:

glab container-registry tag delete <repo-id> latest

Delete tags in bulk (no confirmation):

glab container-registry tag delete-tags <repo-id> --name-regex-delete '^my-branch-.*' --keep-n 5 --older-than 30d -y

Files

Command registration and root command:

• internal/commands/root.go
• internal/commands/container_registry/container_registry.go
• internal/commands/container_registry/container_registry_test.go

Repository commands:

• internal/commands/container_registry/repository/repository.go
• internal/commands/container_registry/repository/repository_test.go
• internal/commands/container_registry/repository/list/list.go
• internal/commands/container_registry/repository/list/list_test.go
• internal/commands/container_registry/repository/view/view.go
• internal/commands/container_registry/repository/view/view_test.go
• internal/commands/container_registry/repository/delete/delete.go
• internal/commands/container_registry/repository/delete/delete_test.go

Tag commands:

• internal/commands/container_registry/tag/tag.go
• internal/commands/container_registry/tag/tag_test.go
• internal/commands/container_registry/tag/list/list.go
• internal/commands/container_registry/tag/list/list_test.go
• internal/commands/container_registry/tag/view/view.go
• internal/commands/container_registry/tag/view/view_test.go
• internal/commands/container_registry/tag/delete/delete.go
• internal/commands/container_registry/tag/delete/delete_test.go
• internal/commands/container_registry/tag/delete_tags/delete_tags.go
• internal/commands/container_registry/tag/delete_tags/delete_tags_test.go

Shared helpers:

• internal/commands/container_registry/registryutils/registryutils.go
• internal/commands/container_registry/registryutils/registryutils_test.go

Documentation:

• README.md
• docs/source/_index.md
• docs/source/container-registry/_index.md
• docs/source/container-registry/repository/_index.md
• docs/source/container-registry/repository/list.md
• docs/source/container-registry/repository/view.md
• docs/source/container-registry/repository/delete.md
• docs/source/container-registry/tag/_index.md
• docs/source/container-registry/tag/list.md
• docs/source/container-registry/tag/view.md
• docs/source/container-registry/tag/delete.md
• docs/source/container-registry/tag/delete-tags.md