fix(cli): separate rich install outcome rendering from plain contracts

[ian-pascoe]

Summary

• split install outcome rendering by output mode so rich TTY output uses a dedicated structured detail path while plain mode preserves deterministic contract lines
• added rich install detail row helpers and tests to enforce badge-free rich rows (STATUS | key: | value) and lock plain output behavior
• updated install flow docs to document the dedicated rich row shape and reaffirm unchanged plain-mode contracts

Verification

• rustup run stable cargo fmt --all --check
• rustup run stable cargo test -p crosspack-cli
• rustup run stable cargo clippy -p crosspack-cli --all-targets -- -D warnings

[ian-pascoe]

@codex review

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. Hooray!

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