* feat(mobile): pick the PR glyph from PR state
Workspace rows always drew the open-PR glyph and only changed its color,
and the PR tab's state badge had no glyph. Both now show merged, closed and
draft glyphs, from one prStateIcon mapping that the details sheet and task
rows also use.
* feat(mobile): show the PR state on the session header's source-control button
The button always drew a branch glyph. When the worktree's catalog row has a
linked PR it now draws that PR's state glyph in its state colour, read from
the host list's worktree.ps query in its own component.
* fix(mobile): read the header's PR state from the catalog cache only
Opening a session must not request worktree.ps before its first paint, so the
source-control button reads what the host list last loaded instead of
fetching it.
