Improve announcement card display and production database usage

Update announcement card UI to match task card styling and integrate PostgreSQL for production announcements, using the `DASHBOARD_MESSAGES` table.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: e437ffed-c31b-44eb-9fd5-b6f9faa8e7ce
Replit-Commit-Checkpoint-Type: full_checkpoint
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/1957c339-2757-4d1f-8e92-e9f71a1ce58e/e437ffed-c31b-44eb-9fd5-b6f9faa8e7ce/BFQBiA5

client/src/components/AnnouncementCard.tsx

@@ -267,10 +267,7 @@ export default function AnnouncementCard() {
   return (
     <Card>
       <CardHeader className="flex flex-row items-center justify-between space-y-0 pb-2">
-        <div className="flex items-center gap-2">
-          <Megaphone className="h-4 w-4 text-muted-foreground" />
-          <CardTitle className="text-sm font-medium">Informations</CardTitle>
-        </div>
+        <CardTitle className="text-sm font-medium">Informations</CardTitle>
         <div className="flex items-center gap-2">
           {user?.role === 'admin' && (
             <Dialog open={isCreateDialogOpen} onOpenChange={(open) => {
@@ -371,6 +368,7 @@ export default function AnnouncementCard() {
               </DialogContent>
             </Dialog>
           )}
+          <Megaphone className="h-4 w-4 text-muted-foreground" />
         </div>
       </CardHeader>
       <CardContent>