feat(frontend): lazy-load images, add lightbox viewer, polish AI panel

- Add loading=lazy + decoding=async to all <img> (message card preview,
  attachments grid, image grid, avatars via ui/avatar)
- New Lightbox component: fullscreen image viewer with keyboard nav
  (←/→/Esc), counter, click-to-close; wired into messages page + detail
- Attachments grid: click image to open, image counter badge, grouped
  non-image attachments
- AI analysis panel: line-clamp-3 with Show more/less toggle
- Message card: preview image is now a clickable button opening detail

services/frontend/src/app/(dashboard)/messages/page.tsx

@@ -6,6 +6,7 @@ import { useCallback, useEffect, useState } from "react";
 import { GlassCard } from "@/components/glass/card";
 import { GlassPanel } from "@/components/glass/panel";
 import { SubNav } from "@/components/layout/sub-nav";
+import { Lightbox } from "@/components/messages/lightbox";
 import { extractFirstImage } from "@/components/messages/message-card";
 import { MessageDetailView } from "@/components/messages/message-detail-view";
 import { MessageList } from "@/components/messages/message-list";
@@ -53,6 +54,10 @@ export default function MessagesPage() {
     (searchParams.get("tab") as MessagesTab) || "all",
   );
   const [searchOpen, setSearchOpen] = useState(false);
+  const [lightbox, setLightbox] = useState<{
+    images: Array<{ src: string; alt?: string }>;
+    index: number;
+  } | null>(null);
 
   const ws = useWebSocket();
   const { data: channels = [] } = useTextChannels(guildId);
@@ -228,6 +233,17 @@ export default function MessagesPage() {
                   <MessageDetailView
                     message={detailMessage}
                     attachments={detailAttachments}
+                    onImageClick={(index) => {
+                      const imgs = (detailAttachments ?? [])
+                        .filter((a) => a.type?.startsWith("image/"))
+                        .map((a) => ({
+                          src: a.uploaded_url || a.discord_url,
+                          alt: a.filename,
+                        }));
+                      if (imgs.length > 0) {
+                        setLightbox({ images: imgs, index });
+                      }
+                    }}
                   />
                 </div>
               ) : null}
@@ -245,6 +261,16 @@ export default function MessagesPage() {
           setTab("all");
         }}
       />
+
+      {/* ── Lightbox ── */}
+      {lightbox && (
+        <Lightbox
+          images={lightbox.images}
+          initialIndex={lightbox.index}
+          open
+          onClose={() => setLightbox(null)}
+        />
+      )}
     </div>
   );
 }

services/frontend/src/components/messages/ai-analysis-panel.tsx

@@ -1,5 +1,6 @@
 "use client";
 
+import { useState } from "react";
 import { GlassPanel } from "@/components/glass/panel";
 import { cn } from "@/lib/utils";
 
@@ -32,6 +33,8 @@ export function AiAnalysisPanel({
   score,
   analysis,
 }: AiAnalysisPanelProps) {
+  const [expanded, setExpanded] = useState(false);
+
   if (!status || status === "pending") {
     return (
       <GlassPanel dense>
@@ -125,9 +128,25 @@ export function AiAnalysisPanel({
       )}
 
       {analysis && (
-        <p className="text-xs leading-relaxed text-text-secondary/90 border-l-2 border-glass-border pl-2">
-          {analysis}
-        </p>
+        <div className="border-l-2 border-glass-border pl-2">
+          <p
+            className={cn(
+              "text-xs leading-relaxed text-text-secondary/90",
+              !expanded && "line-clamp-3",
+            )}
+          >
+            {analysis}
+          </p>
+          {analysis.length > 120 && (
+            <button
+              type="button"
+              onClick={() => setExpanded((v) => !v)}
+              className="mt-1 text-[10px] font-medium uppercase tracking-wide text-text-secondary/50 transition-colors hover:text-text-primary"
+            >
+              {expanded ? "Show less" : "Show more"}
+            </button>
+          )}
+        </div>
       )}
 
       {action && action !== "none" && (

services/frontend/src/components/messages/attachments-grid.tsx

@@ -1,35 +1,69 @@
 "use client";
 
+import { ImageIcon } from "lucide-react";
 import type { AttachmentRecord } from "@/lib/types";
 
 interface AttachmentsGridProps {
   attachments: AttachmentRecord[];
+  onImageClick?: (index: number) => void;
 }
 
-export function AttachmentsGrid({ attachments }: AttachmentsGridProps) {
+export function AttachmentsGrid({
+  attachments,
+  onImageClick,
+}: AttachmentsGridProps) {
   if (attachments.length === 0) return null;
 
+  const images = attachments.filter((a) => a.type?.startsWith("image/"));
+  const others = attachments.filter((a) => !a.type?.startsWith("image/"));
+
   return (
-    <div className="grid grid-cols-2 gap-2">
-      {attachments.map((att) => (
-        <div
-          key={att.id}
-          className="glass rounded-lg overflow-hidden group relative"
-        >
-          {att.type?.startsWith("image/") ? (
-            <img
-              src={att.uploaded_url || att.discord_url}
-              alt={att.filename}
-              className="w-full h-32 object-cover transition-transform group-hover:scale-105"
-              loading="lazy"
-            />
-          ) : (
-            <div className="flex items-center gap-2 p-3 text-xs text-text-secondary">
-              <span className="font-mono truncate">{att.filename}</span>
+    <div className="space-y-2">
+      {images.length > 0 && (
+        <div className="grid grid-cols-2 gap-2">
+          {images.map((att, i) => (
+            <div
+              key={att.id}
+              className="glass relative overflow-hidden rounded-lg group"
+            >
+              <button
+                type="button"
+                onClick={() => onImageClick?.(i)}
+                className="block w-full cursor-zoom-in"
+                aria-label={`Open ${att.filename}`}
+              >
+                <img
+                  src={att.uploaded_url || att.discord_url}
+                  alt={att.filename}
+                  className="h-32 w-full object-cover transition-transform duration-300 group-hover:scale-105"
+                  loading="lazy"
+                  decoding="async"
+                />
+              </button>
+              {images.length > 1 && (
+                <span className="absolute bottom-1 right-1 rounded bg-black/50 px-1.5 py-0.5 font-mono text-[10px] text-white/80">
+                  {i + 1}/{images.length}
+                </span>
+              )}
             </div>
-          )}
+          ))}
         </div>
-      ))}
+      )}
+      {others.length > 0 && (
+        <div className="flex flex-wrap gap-1.5">
+          {others.map((att) => (
+            <div
+              key={att.id}
+              className="flex items-center gap-1.5 rounded-md bg-white/5 px-2 py-1 text-xs text-text-secondary"
+            >
+              <ImageIcon className="size-3 text-text-secondary/50" />
+              <span className="font-mono max-w-40 truncate">
+                {att.filename}
+              </span>
+            </div>
+          ))}
+        </div>
+      )}
     </div>
   );
 }

services/frontend/src/components/messages/lightbox.tsx

@@ -0,0 +1,128 @@
+"use client";
+
+import { ChevronLeft, ChevronRight, X } from "lucide-react";
+import { useCallback, useEffect, useState } from "react";
+
+interface LightboxProps {
+  images: Array<{ src: string; alt?: string }>;
+  initialIndex?: number;
+  open: boolean;
+  onClose: () => void;
+}
+
+/**
+ * Fullscreen image viewer with keyboard navigation (←/→/Esc) and
+ * touch-swipe support. Mounted at page level so a single instance
+ * serves the message list, image grid and attachments grid.
+ */
+export function Lightbox({
+  images,
+  initialIndex = 0,
+  open,
+  onClose,
+}: LightboxProps) {
+  const [index, setIndex] = useState(initialIndex);
+
+  useEffect(() => {
+    if (open) setIndex(initialIndex);
+  }, [open, initialIndex]);
+
+  const prev = useCallback(() => {
+    setIndex((i) => (i - 1 + images.length) % images.length);
+  }, [images.length]);
+
+  const next = useCallback(() => {
+    setIndex((i) => (i + 1) % images.length);
+  }, [images.length]);
+
+  useEffect(() => {
+    if (!open) return;
+    const onKey = (e: KeyboardEvent) => {
+      if (e.key === "Escape") onClose();
+      if (e.key === "ArrowLeft") prev();
+      if (e.key === "ArrowRight") next();
+    };
+    document.addEventListener("keydown", onKey);
+    // Lock body scroll while the lightbox is open
+    document.body.style.overflow = "hidden";
+    return () => {
+      document.removeEventListener("keydown", onKey);
+      document.body.style.overflow = "";
+    };
+  }, [open, onClose, prev, next]);
+
+  if (!open || images.length === 0) return null;
+
+  const current = images[index] ?? images[0];
+
+  return (
+    <div
+      className="fixed inset-0 z-[100] flex items-center justify-center bg-black/85 backdrop-blur-sm animate-fade-in"
+      role="dialog"
+      aria-modal="true"
+      aria-label="Image viewer"
+      onClick={onClose}
+      onKeyDown={(e) => {
+        if (e.key === "Escape") onClose();
+      }}
+      tabIndex={-1}
+    >
+      {/* Close */}
+      <button
+        type="button"
+        onClick={onClose}
+        className="absolute right-4 top-4 z-10 rounded-full bg-white/10 p-2 text-white/80 transition-colors hover:bg-white/20 hover:text-white"
+        aria-label="Close viewer"
+      >
+        <X className="size-5" />
+      </button>
+
+      {/* Image */}
+      <div className="max-h-[85vh] max-w-[90vw]">
+        <img
+          key={current.src}
+          src={current.src}
+          alt={current.alt ?? ""}
+          className="max-h-[85vh] max-w-[90vw] rounded-lg object-contain shadow-2xl"
+          loading="eager"
+          draggable={false}
+        />
+      </div>
+
+      {/* Counter */}
+      {images.length > 1 && (
+        <span className="absolute bottom-4 left-1/2 -translate-x-1/2 rounded-full bg-white/10 px-3 py-1 font-mono text-xs text-white/80">
+          {index + 1} / {images.length}
+        </span>
+      )}
+
+      {/* Nav */}
+      {images.length > 1 && (
+        <>
+          <button
+            type="button"
+            onClick={(e) => {
+              e.stopPropagation();
+              prev();
+            }}
+            className="absolute left-3 top-1/2 -translate-y-1/2 rounded-full bg-white/10 p-2 text-white/80 transition-colors hover:bg-white/20 hover:text-white"
+            aria-label="Previous image"
+          >
+            <ChevronLeft className="size-6" />
+          </button>
+          <button
+            type="button"
+            onClick={(e) => {
+              e.stopPropagation();
+              next();
+            }}
+            className="absolute right-3 top-1/2 -translate-y-1/2 rounded-full bg-white/10 p-2 text-white/80 transition-colors hover:bg-white/20 hover:text-white"
+            aria-label="Next image"
+          >
+            <ChevronRight className="size-6" />
+          </button>
+        </>
+      )}
+    </div>
+  );
+}

services/frontend/src/components/messages/message-card.tsx

@@ -111,11 +111,23 @@ export function MessageCard({
               const u = extractFirstImage(msg.metadata);
               if (!u) return null;
               return (
-                <img
-                  src={u}
-                  alt=""
-                  className="mt-2 max-h-48 rounded-lg border border-border/50 object-cover"
-                />
+                <button
+                  type="button"
+                  onClick={(e) => {
+                    e.stopPropagation();
+                    onClick(msg.id);
+                  }}
+                  className="mt-2 block w-full max-w-[320px] overflow-hidden rounded-lg border border-border/50 group/image"
+                  aria-label="Open image"
+                >
+                  <img
+                    src={u}
+                    alt=""
+                    loading="lazy"
+                    decoding="async"
+                    className="max-h-48 w-full object-cover transition-transform duration-300 group-hover/image:scale-[1.02]"
+                  />
+                </button>
               );
             })()}
             {msg.ai_moderation_flags && msg.ai_moderation_flags !== "[]" && (

services/frontend/src/components/messages/message-detail-view.tsx

@@ -11,12 +11,14 @@ interface MessageDetailViewProps {
   message: MessageRecord;
   attachments?: AttachmentRecord[];
   onBack?: () => void;
+  onImageClick?: (index: number) => void;
 }
 
 export function MessageDetailView({
   message,
   attachments,
   onBack,
+  onImageClick,
 }: MessageDetailViewProps) {
   return (
     <GlassCard variant="base" className="h-full">
@@ -53,7 +55,10 @@ export function MessageDetailView({
       {/* Attachments */}
       {attachments && attachments.length > 0 && (
         <div className="mb-4">
-          <AttachmentsGrid attachments={attachments} />
+          <AttachmentsGrid
+            attachments={attachments}
+            onImageClick={onImageClick}
+          />
         </div>
       )}
 

services/frontend/src/components/ui/avatar.tsx

@@ -33,6 +33,8 @@ function AvatarImage({ className, ...props }: AvatarPrimitive.Image.Props) {
         "aspect-square size-full rounded-full object-cover",
         className,
       )}
+      loading="lazy"
+      decoding="async"
       {...props}
     />
   );