feat(models): add box activity tracking

Adds BoxActivity model to track actions taken on a box.
Updates related endpoints and UI for activity feed.

static/css/account.css

@@ -1040,6 +1040,53 @@ textarea:disabled {
     padding: 8px;
 }
 
+.box-manager-layout {
+    display: grid;
+    grid-template-rows: auto auto minmax(0, 1fr);
+    gap: 10px;
+    min-height: min(940px, calc(100vh - 96px));
+}
+
+.box-manager-grid {
+    min-height: 0;
+    display: grid;
+    grid-template-columns: minmax(0, 1.35fr) minmax(300px, .65fr);
+    gap: 10px;
+}
+
+.box-manager-main,
+.box-manager-side {
+    min-height: 0;
+    display: grid;
+    gap: 10px;
+    align-content: start;
+}
+
+.files-scroll {
+    height: 430px;
+    overflow-x: auto;
+}
+
+.policy-pre {
+    max-height: 220px;
+    min-height: 160px;
+}
+
+.activity-list-compact {
+    display: grid;
+}
+
+.activity-list-compact .activity-row {
+    grid-template-columns: 132px minmax(0, 1fr);
+}
+
+.activity-list-compact .activity-title,
+.activity-list-compact .activity-meta {
+    overflow: hidden;
+    text-overflow: ellipsis;
+    white-space: nowrap;
+}
+
 .scroll-panel {
     overflow: auto;
     color: #000000;
@@ -1321,6 +1368,10 @@ textarea:disabled {
         grid-template-columns: 1fr;
     }
 
+    .box-manager-grid {
+        grid-template-columns: 1fr;
+    }
+
     .alerts-filterbar {
         grid-template-columns: repeat(2, minmax(0, 1fr));
     }
@@ -1460,6 +1511,10 @@ textarea:disabled {
         height: 420px;
     }
 
+    .files-scroll {
+        height: 360px;
+    }
+
     .win98-window-controls {
         display: none;
     }