azd ai toolbox version is shadowed by the toolbox version subgroup

[hund030]

Output from azd version

azd version 1.25.2 (commit 528dda5) (stable)

toolkit extension built from main (commit ee35996).

Describe the bug

azure.ai.toolboxes registers two commands at the root with the same Use: "version" (root.go:49 and root.go:52).
Cobra resolves to the first one registered — the toolbox-versions subgroup — so the standard extension-version command from azdext.NewVersionCommand is unreachable.

To Reproduce

azd ai toolbox version
# Prints help for "Inspect toolbox versions." (the subgroup),
# not the extension name + version.
azd ai toolbox version --output json
# Same — falls into the subgroup, no JSON emitted.
For comparison:
azd ai agent version --output json
# {"name":"azure.ai.agents","version":"..."}

Expected behavior
azd ai toolbox version should print the extension name and version, like every other azd extension.

proposed fix

Rename the subgroup to versions

azd ai toolbox version            # extension version (fixed)
azd ai toolbox versions list <tb> # list published versions