Fix historical DM packet length passing and fix up some docs

frontend/src/App.tsx

@@ -694,7 +694,10 @@ export function App() {
           </SheetContent>
         </Sheet>
 
-        <main id="main-content" className="flex-1 flex flex-col bg-background min-w-0">
+        <main
+          id="main-content"
+          className="flex-1 flex flex-col bg-background min-w-0 min-h-0 overflow-hidden"
+        >
           <div
             className={cn(
               'flex-1 flex flex-col min-h-0',
@@ -734,7 +737,7 @@ export function App() {
                   <h2 className="flex justify-between items-center px-4 py-2.5 border-b border-border font-semibold text-base">
                     Raw Packet Feed
                   </h2>
-                  <div className="flex-1 overflow-hidden">
+                  <div className="flex-1 min-h-0 overflow-hidden relative">
                     <RawPacketList packets={rawPackets} />
                   </div>
                 </>

frontend/src/components/RawPacketList.tsx

@@ -202,14 +202,14 @@ export function RawPacketList({ packets }: RawPacketListProps) {
 
   if (packets.length === 0) {
     return (
-      <div className="h-full overflow-y-auto p-5 text-center text-muted-foreground">
+      <div className="absolute inset-0 overflow-y-auto p-5 text-center text-muted-foreground">
         No packets received yet. Packets will appear here in real-time.
       </div>
     );
   }
 
   return (
-    <div className="h-full overflow-y-auto p-4 flex flex-col gap-2" ref={listRef}>
+    <div className="absolute inset-0 overflow-y-auto p-4 flex flex-col gap-2" ref={listRef}>
       {sortedPackets.map(({ packet, decoded }) => (
         <div
           key={getRawPacketObservationKey(packet)}