List root tasks as compact lines: ``<sign> <id>  <title> (...)``.

Status signs: ``.`` pending, ``~`` in-progress, ``?`` in-review,
``x`` done, ``-`` cancelled. A trailing ``(...)`` marks a task that has
a body -- view it for the full detail.

Args:
    todo: If True, list only tasks from the TODO list.

Each task renders as ``# <id>: <full title>`` followed by ``status:`` /
``parent:`` metadata lines (``parent:`` omitted for root tasks), the
verbatim task body, and a ``## Subtasks`` checklist reusing the compact
line format. A bad/deleted/unknown ref becomes a ``# <ref>: <error>`` stub
instead of failing the batch. Blocks are joined by ``\n\n---\n\n``.

Use this instead of reading task files from disk.