feat(lists): read and show the list cap on every capped list

Twelve routes answer a capped list with meta.truncated / meta.limit on
the envelope, and the web client read only data, so no surface said a
list had stopped short. apiGetList / apiPostList are now the one client
reader of the cap and ListCapNotice the one line that shows it; every
capped list on the web reads its cap and shows the notice under the list,
the paged readers (side effects, illness episodes) stop on the route's
answer instead of a full-page guess, and the ECG list moves its five
readers onto one hook. The record activity feed sent its cap twice, in
data and on the envelope; it rides the envelope alone now. A guard
derives the capped routes from the tree and binds each to a client that
reads its cap.

docs/api/openapi.yaml

@@ -21436,7 +21436,8 @@ paths:
         per day with a count, rather than one per request. `retentionDays` rides the response because audit history is
         purged on a schedule the operator configures: a view that showed the rows without the window would imply a
         completeness it does not have, and clients must state the number the server sends rather than assume the 365-day
-        default. Not delegable: a grant is not an introduction to the other people in the household."
+        default. Whether the list stopped at its row ceiling is `meta.truncated` (it was a `truncated` field in `data`
+        before v1.43.7). Not delegable: a grant is not an introduction to the other people in the household."
       responses:
         "200":
           description: The activity, and how far back it can see.
@@ -81390,15 +81391,9 @@ components:
           description: How far back this feed can see, in days. Resolved from the instance's audit retention setting (365 by
             default, operator-configurable), NOT a constant — an instance running a 90-day window sends 90. The query is
             bounded to this window, so it is the real limit of the list and not only a caption. Show it beside the rows.
-        truncated:
-          type: boolean
-          description: True when the read reached its row ceiling, so `entries` is the most recent activity inside the window
-            rather than all of it. A client must say so — a list that stops at its own cap in silence lets the oldest
-            row read as the beginning. False means the list is everything inside the window.
       required:
         - entries
         - retentionDays
-        - truncated
       additionalProperties: false
       description: The owner's record of what somebody else did in their record, bounded by the instance's audit retention.
     RecordActivityEntry: