chore(agents): streamline some command interactions and minor bugs

[rektdeckard]

Various improvements to lk agents flows:

• Better ergonomics around some commands, prompt for missing values
• Consistent application theme
• Fixed some erroneous early returns and errors

[ilo-nanpa]

it seems like you haven't added any nanpa changeset files to this PR.

if this pull request includes changes to code, make sure to add a changeset, by writing a file to .nanpa/<unique-name>.kdl:

minor type="added" "Introduce frobnication algorithm"

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