refactor(products): split migrated product commands

[Episkey-G]

Summary

• Split migrated command groups into independent product directories while preserving user-facing commands.
• Rename product ownership directories for GlobalSSH and shared bandwidth to products/globalssh and products/sharedbw while keeping gssh and bw command paths.
• Regenerate product registration/goldens, update product registration tests, and add structured output coverage for uhost create-image.

Validation

• go run ./hack/check-product
• go test ./... -skip TestUhost -count=1
• P4 real-billing E2E was run locally before PR; created resources were cleaned up. Remaining environment blockers: gssh create account compliance and pathx service unavailable in cn-bj2.

Notes

• Local untracked planning docs/TODOS are intentionally not included in this PR.