Shorten empty states and composer status copy

The transcript's empty state suggested asking the planner to draft something or
to read the repository — a cold start hint, sitting two inches above the box you
would type it into. The hint is worth keeping and the second surface is not, so
it moves into the composer's placeholder, which is attached to the thing it
describes and disappears the moment you begin.

The decisions pane opened with three clauses: select prose to comment on it,
questions appear here too, both stay as a record. Only the first is undiscoverable
by looking. The other two describe what the reader watches happen the first time
it happens, so they are gone.

The composer's own status line stays. It is what stops somebody typing into what
looks like a prompt and meeting silence, and both halves carry weight — where the
message is going, and that it is not lost. Shortened rather than cut, and left in
the lower case its sibling beside it uses.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>