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/main.tsx

@@ -2,6 +2,7 @@ import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
 import React from "react";
 import ReactDOM from "react-dom/client";
 import App from "./App";
+import { ToastProvider } from "./shared/ui";
 import "./styles.css";
 
 const queryClient = new QueryClient({
@@ -24,7 +25,9 @@ if (!root) {
 ReactDOM.createRoot(root).render(
   <React.StrictMode>
     <QueryClientProvider client={queryClient}>
-      <App />
+      <ToastProvider>
+        <App />
+      </ToastProvider>
     </QueryClientProvider>
   </React.StrictMode>,
 );