feat: improve ChatMediaRenderer UX

- Full dotted border with rounded corners (was bottom-only)
- Increased gap between elements
- Images/videos open in MediaDialog zoom viewer on click
- Audio still opens in new tab
- Better extension extraction for display

https://claude.ai/code/session_01AeeN5d5EcVLGjZbGueZxaD

src/components/chat/ChatMediaRenderer.tsx

@@ -5,12 +5,31 @@
  * [icon] filename [size] [blossom-link]
  */
 
+import { useState } from "react";
 import { Image, Video, Music, File, Flower2 } from "lucide-react";
 import { getHashFromURL } from "blossom-client-sdk/helpers/url";
 import { useGrimoire } from "@/core/state";
 import { formatFileSize } from "@/lib/imeta";
+import { MediaDialog } from "@/components/nostr/MediaDialog";
 import type { MediaRendererProps } from "@/components/nostr/RichText";
 
+/**
+ * Extract file extension from URL
+ */
+function getExtension(url: string): string | null {
+  try {
+    const urlObj = new URL(url);
+    const pathname = urlObj.pathname;
+    const lastSegment = pathname.split("/").pop() || "";
+    if (lastSegment.includes(".")) {
+      return lastSegment.split(".").pop() || null;
+    }
+    return null;
+  } catch {
+    return null;
+  }
+}
+
 /**
  * Extract filename from URL
  */
@@ -22,7 +41,7 @@ function getFilename(url: string): string {
     // If it's a blossom hash, truncate it
     const hash = getHashFromURL(url);
     if (hash) {
-      const ext = lastSegment.includes(".") ? lastSegment.split(".").pop() : "";
+      const ext = getExtension(url);
       return ext ? `${hash.slice(0, 8)}...${ext}` : `${hash.slice(0, 8)}...`;
     }
     // Decode URI component for readable filenames
@@ -69,6 +88,7 @@ function MediaIcon({ type }: { type: "image" | "video" | "audio" }) {
 
 export function ChatMediaRenderer({ url, type, imeta }: MediaRendererProps) {
   const { addWindow } = useGrimoire();
+  const [dialogOpen, setDialogOpen] = useState(false);
 
   const filename = imeta?.alt || getFilename(url);
   const size = imeta?.size ? formatFileSize(imeta.size) : null;
@@ -86,35 +106,47 @@ export function ChatMediaRenderer({ url, type, imeta }: MediaRendererProps) {
     }
   };
 
-  const handleFileClick = (e: React.MouseEvent) => {
+  const handleMediaClick = (e: React.MouseEvent) => {
+    e.preventDefault();
     e.stopPropagation();
+    // Images and videos open in dialog, audio opens in new tab
+    if (type === "image" || type === "video") {
+      setDialogOpen(true);
+    } else {
+      window.open(url, "_blank", "noopener,noreferrer");
+    }
   };
 
   return (
-    <span className="inline-flex items-center gap-1 border-b border-dotted border-muted-foreground/50">
-      <MediaIcon type={type} />
-      <a
-        href={url}
-        target="_blank"
-        rel="noopener noreferrer"
-        onClick={handleFileClick}
-        className="text-foreground hover:underline truncate max-w-48"
-        title={imeta?.alt || url}
-      >
-        {filename}
-      </a>
-      {size && (
-        <span className="text-muted-foreground text-xs shrink-0">{size}</span>
-      )}
-      {blossom && (
+    <>
+      <span className="inline-flex items-center gap-1.5 border border-dotted border-muted-foreground/40 rounded px-1">
+        <MediaIcon type={type} />
         <button
-          onClick={handleBlossomClick}
-          className="text-muted-foreground hover:text-foreground"
-          title="View in Blossom"
+          onClick={handleMediaClick}
+          className="text-foreground hover:underline truncate max-w-48 text-left"
+          title={imeta?.alt || url}
         >
-          <Flower2 className="size-3" />
+          {filename}
         </button>
-      )}
-    </span>
+        {size && (
+          <span className="text-muted-foreground text-xs shrink-0">{size}</span>
+        )}
+        {blossom && (
+          <button
+            onClick={handleBlossomClick}
+            className="text-muted-foreground hover:text-foreground"
+            title="View in Blossom"
+          >
+            <Flower2 className="size-3" />
+          </button>
+        )}
+      </span>
+      <MediaDialog
+        open={dialogOpen}
+        onOpenChange={setDialogOpen}
+        urls={[url]}
+        initialIndex={0}
+      />
+    </>
   );
 }