fix(output): render next actions for custom views

[sswaminathan-godaddy]

Objective

Make human output consistent for commands that register a custom human renderer: preserve the renderer body and append the standard Next steps: footer from the command result.

Changes

• Append existing envelope next actions after a custom human renderer returns.
• Reuse cli-engine's existing parameter substitution and footer behavior.
• Add focused integration coverage for a custom view with a parameterized next action.
• Move the focused test to its own integration-test file to retain the 1,000-line module limit.

Verification

cargo fmt --all --check
cargo clippy --all-targets -- -D warnings
RUSTDOCFLAGS='-D warnings' cargo doc --package cli-engine --no-deps
cargo test --all-targets
cargo test --doc
./cli-engine/scripts/check-module-size.sh

All passed.

🤖 Generated with Claude Code