feat(talk): replace text type prefixes with emojis in messages

- Extract `typeIcon` from mapped data in `WebhookController` and pass to `prependDisplayName`
- Update `TalkService.prependDisplayName` to accept optional `$typeIcon` parameter and prepend it to the display name line
- Remove text-based type labels (`[Info]`, `[Success]`, `[Warning]`, `[Error]`) and replace with emoji icons (`✅`, `⚠️`, `❌`)
- Include `typeIcon` in the message payload array returned by `TalkService`

lib/Controller/WebhookController.php

@@ -473,7 +473,8 @@ class WebhookController extends Controller {
 
         // Prepend display name since Talk doesn't support per-message avatars
         $displayName = $mapped['displayName'] ?? $senderName;
-        $message = $this->talkService->prependDisplayName($displayName, $mapped['message']);
+        $typeIcon = $mapped['typeIcon'] ?? '';
+        $message = $this->talkService->prependDisplayName($displayName, $mapped['message'], $typeIcon);
 
         // Post to Talk via Chat API
         $success = $this->talkService->postToRoom($roomToken, $message, $senderName, $richObjects);