$starship_prompt includes $line_break and $character output

[evenkeelhuang]

Description

When using $starship_prompt in cship.toml, the rendered output includes $line_break and $character from the user's starship.toml format string. This causes an extra line with the prompt character (e.g. ❯) to appear below the starship prompt row in the status line.

Steps to Reproduce

1. Have a starship.toml with a format that includes $line_break and $character:

   format = """
   [](red)\
   $os\
   ...
   $time\
   [ ](fg:lavender)\
   $cmd_duration\
   $line_break\
   $character"""

2. Use $starship_prompt in cship.toml:

   [cship]
   lines = ["$starship_prompt", "$cship.model $cship.context_bar"]

3. The status line renders an unwanted extra line containing ❯ between the starship row and the cship modules row.

Expected Behavior

$starship_prompt should strip $line_break and $character (and possibly $cmd_duration) from the output, since these are interactive shell prompt elements that don't make sense in a status line context.

Environment

• cship v1.3.0
• macOS (aarch64)
• Starship installed