feat: comprehensive UX improvements — messages, analysis, moderation

Fix #1 (CRITICAL): Wire message_analyzed through Redis EventBroadcaster
- DG aiAnalyzer.ts: Add broadcastAnalysisCompleted() helper that publishes
  to both in-memory WS broadcaster AND Redis EventBroadcaster
- DG bootstrap.ts: Pass eventBroadcaster to startPendingAIAnalysisWorker()
- Fixes broken real-time chain so analysis results appear instantly

Fix #2: Collapsible AI Analysis with Rich Formatting
- MessageCard: AI analysis now collapsible with color-coded severity border
  (red/yellow/blue), summary line showing categories + confidence + severity
- Default collapsed for clean, expanded for warn/flagged

Fix #3: Toast Notifications for Flagged Content
- Wrap app in ToastProvider; ModerationAlertListener component listens for
  moderation_alert custom events and shows toast with emoji + details

Fix #4: Discord-style Message Grouping
- MessageFeed: Group consecutive messages from same user within 5 min
- MessageCard: Compact variant hides avatar, reduces padding for non-first

Fix #5: Moderation Action Buttons in UI
- BE: POST /api/messages/:id/moderate endpoint + publishCommand() for Redis
- FE: Delete/Warn buttons on flagged/warned cards with confirmation dialog

Fix #6: Search Results Include Full Data
- BE analysis.service.ts: SELECT all 26 message columns instead of just 11
- Search results now render with full MessageCard including images/analysis

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

services/frontend/src/features/messages/components/MessageFeed.tsx

@@ -1,4 +1,4 @@
-import { useEffect, useRef } from "react";
+import { useEffect, useMemo, useRef } from "react";
 import type { MessageRecord } from "../../../shared/api/client";
 import { ScrollArea } from "../../../shared/ui";
 import { MessageCard, MessageCardSkeleton } from "./MessageCard";
@@ -13,6 +13,32 @@ export interface MessageFeedProps {
   loadingMore?: boolean;
 }
 
+/** Messages from the same user within 5 minutes are visually grouped. */
+const GROUP_WINDOW_MS = 5 * 60 * 1000;
+
+interface MessageGroup {
+  messages: MessageRecord[];
+}
+
+function groupMessages(messages: MessageRecord[]): MessageGroup[] {
+  const groups: MessageGroup[] = [];
+  for (const msg of messages) {
+    const lastGroup = groups[groups.length - 1];
+    if (
+      lastGroup &&
+      lastGroup.messages[0].user_id === msg.user_id &&
+      lastGroup.messages[lastGroup.messages.length - 1].created_at -
+        msg.created_at <
+        GROUP_WINDOW_MS
+    ) {
+      lastGroup.messages.push(msg);
+    } else {
+      groups.push({ messages: [msg] });
+    }
+  }
+  return groups;
+}
+
 export function MessageFeed({
   messages,
   onReanalyze,
@@ -40,6 +66,8 @@ export function MessageFeed({
     return () => observer.disconnect();
   }, [onLoadMore, hasMore]);
 
+  const groupedMessages = useMemo(() => groupMessages(messages), [messages]);
+
   if (loading) {
     return (
       <ScrollArea className="h-[calc(100vh-260px)] pr-3">
@@ -63,13 +91,20 @@ export function MessageFeed({
   return (
     <ScrollArea className="h-[calc(100vh-260px)] pr-3">
       <div className="space-y-3">
-        {messages.map((message) => (
-          <MessageCard
-            key={message.id}
-            message={message}
-            onReanalyze={onReanalyze}
-          />
-        ))}
+        {groupedMessages.map((group) =>
+          group.messages.map((message, idx) => {
+            const isFirstInGroup = idx === 0;
+            const isCompact = !isFirstInGroup;
+            return (
+              <MessageCard
+                key={message.id}
+                message={message}
+                onReanalyze={onReanalyze}
+                compact={isCompact}
+              />
+            );
+          }),
+        )}
 
         {/* Infinite-scroll sentinel */}
         {hasMore && (