T22 round 1 fixes

- a remote cursor shows only while its caret sits inside the field, sideways too
- presence avatars keep a transparent border for the focus ring
- the access list shows each role, as words when it cannot change
- status dots take the theme's size
- peer and member pictures load from files and web addresses alike

TASKS.md

@@ -254,3 +254,4 @@ Per-component lines live in `tasks/`. Tags there:
 | T21c | 1 | FAIL | the gallery's page properties dropped a new due date and tags |
 | T21b | 2 | PASS | |
 | T21c | 2 | PASS | |
+| T22 | 1 | FAIL | a remote cursor scrolled out sideways still drew its flag; presence avatars showed no focus ring; the access list hid roles it could not change; status dots used a fixed size |