merge: integrate upstream changes with multi-device federation

muxplex/frontend/style.css

@@ -239,6 +239,30 @@ body {
   margin: 0;
 }
 
+/* Loading placeholder tile — shown while a new session is being created */
+.tile--loading {
+  opacity: 0.6;
+  pointer-events: none;
+}
+
+.tile--loading .tile-body pre {
+  background: repeating-linear-gradient(
+    90deg,
+    var(--border) 0px,
+    var(--bg-surface) 30px,
+    var(--border) 60px
+  );
+  background-size: 200% 100%;
+  animation: shimmer 1.5s ease-in-out infinite;
+  min-height: 60px;
+  border-radius: 2px;
+}
+
+@keyframes shimmer {
+  0% { background-position: 200% 0; }
+  100% { background-position: -200% 0; }
+}
+
 .tile-pre {
   position: absolute;
   inset: 0;
@@ -1492,6 +1516,27 @@ body {
   padding: 8px 12px 4px;
 }
 
+/* ============================================================
+   Dashboard view modes — Fit
+   ============================================================ */
+
+/* Fit view — tiles fill viewport, no scroll */
+.session-grid--fit {
+  overflow: hidden;
+}
+
+/* In fit mode, stretch pre to fill the full tile body height and anchor content to bottom */
+.session-grid--fit .tile-body pre {
+  top: 0;                   /* stretch to fill full tile body height in fit mode */
+  overflow-y: scroll;       /* enable scrollTop positioning (content anchored via JS scrollTop=scrollHeight) */
+  scrollbar-width: none;    /* Firefox: hide scrollbar */
+  -ms-overflow-style: none; /* IE/Edge: hide scrollbar */
+}
+
+.session-grid--fit .tile-body pre::-webkit-scrollbar {
+  display: none;            /* Chrome/Safari: hide scrollbar */
+}
+
 /* ============================================================
    Responsive overlay sidebar at <960px
    ============================================================ */