feat: the model's short name up to 12 characters

internal/server/web/static/app.css

@@ -963,7 +963,7 @@ dialog.uidlg { width:fit-content; min-width:min(300px, 92vw); max-width:min(560p
    pointed at; the list opens upwards, as a small card. */
 .ai-mpick { position:relative; margin-left:auto; min-width:0; }
 .ai-mpick[hidden] { display:none; }
-/* A short name (9 characters at most) is shown whole. */
+/* A short name (12 characters at most) is shown whole. */
 .ai-mpick.short { flex-shrink:0; }
 .ai-mbtn { display:inline-flex; align-items:center; gap:3px; max-width:100%; height:28px; padding:0 5px 0 7px; border:0; border-radius:8px;
            background:transparent; color:var(--muted); font-size:12.5px; font-weight:500; transition:background-color .15s, color .15s; }