feat(command): Add bare group help Json output support

[mguerrero3-godaddy]

Summary

• Reimplements feat(command): Add BareGroupAction support #76 based on several ideas shared on that PR. Simpler, no bare group actions to define by consumers on each command, but a default general behavior reusing thetree --json command scoping to the location of that group command.

NOTE: This isn't implementing the --help --json approach, this just ensures that bare group commands now expose their subcommand tree as structured, machine-readable discovery output by default, instead of silently falling back to human-oriented clap help text that a script or agent can't parse. The discussion to implement --help --json is opened as an idea from @jpage-godaddy and can be implemented here or in a separate PR.

Test plan

• cargo fmt --all --check
• cargo clippy --all-targets -- -D warnings
• cargo test --all-targets

Manual verification

Setup:

# In the cli repo, temporarily override the engine dependency:
cd cli/rust
# Edit Cargo.toml → cli-engine = { features = ["pkce-auth"], path = "../../cli-engine" }
cargo build --release && cp target/release/gddy ~/.local/bin/gddy

Test WITHOUT the fix (baseline):

cd cli-engine && git checkout main
cd cli/rust && cargo build --release && cp target/release/gddy ~/.local/bin/gddy
# <command to reproduce the issue>
# Expected: <describe broken behavior>

Test WITH the fix:

cd cli-engine && git checkout <this-branch>
cd cli/rust && cargo build --release && cp target/release/gddy ~/.local/bin/gddy
# <same command>
# Expected: <describe fixed behavior>

Cleanup:

# Revert cli/rust/Cargo.toml back to:
# cli-engine = { features = ["pkce-auth"], version = "<published-version>" }