When a label is given it is now used verbatim as the slug (no random
suffix), so two launches with the same label collide by design. The
CLI re-prompts via the TUI name modal with a disclaimer when the
candidate slug is already in use among running bottles.
When a user names a bottle via the TUI label field, that name is now
used as the slug prefix for the container identity instead of always
falling back to the agent name.