A crowd you can find, and a phone 65px too narrow

Two reports against 1.6.0 and 1.7.0, both correct.

The crowd worked end to end and was, in practice, not there: the picker was
behind the ⋯ menu of a chat that already existed, and the switch was a card on
the Agents page, which made it read as an agent-chat feature. The picker is now
a button in the composer toolbar on both screens that include it, and on the
new-chat screen the choice rides along with the first message, so a chat can
start as a crowd instead of having to be converted into one. The instance
switch has its own page.

The width bug was the suggestion cards, exactly as reported. `.suggestions`
rendered 455px inside a 366px column, and the tree's standing rule applied on
its own made it worse -- 428px to 455px. A grid item carries `min-width: auto`,
which is a min-content floor, and a floor beats `width: 100%`; the floor is
measured while the percentage is indefinite, so `min(100%, …)` alone sends the
track to a card's max-content. Both halves now go on all four auto-fit grids,
and a test refuses either alone.

It survived four releases of narrow-width checking because the harness never
rendered that screen: `TestClient(app)` runs no lifespan outside a `with` block,
so the startup-seeded cards were missing from every shot ever taken of it. And
its overflow check skipped anything inside a scroller -- right for a table in
its own scroller, blind to the scroller itself, which `overflow-y: auto` makes
scroll sideways too. Both fixed; it now names the box and the child to blame.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/lembas/web/templates/admin/_layout.html

@@ -50,6 +50,13 @@
           {{ icon("sliders", "icon--sm") }}
           <span class="nav-item__label">{{ t("Models") }}</span>
         </a>
+        {# Its own entry rather than a card on Agents, where it started. Sitting
+           there made it read as an agent-chat feature -- which is what the owner
+           took it for, reasonably, since that is what the page is called. #}
+        <a class="nav-item {{ 'is-active' if section == 'crowd' }}" href="/admin/crowd">
+          {{ icon("users", "icon--sm") }}
+          <span class="nav-item__label">{{ t("A crowd") }}</span>
+        </a>
         <a class="nav-item {{ 'is-active' if section == 'audio' }}" href="/admin/audio">
           {{ icon("speaker", "icon--sm") }}
           <span class="nav-item__label">{{ t("Audio") }}</span>