feat(ai-moderation): rich context + link media vision analysis

- Conversation context recency gates (GAP_MS/MAX_AGE_MS): drop stale
  messages before silence gaps; cold_start anchor + flow descriptor
  tells LLM whether conversation is ongoing or restarted
- [location] block: channel name, thread name, nsfw/age flags from
  captured metadata (thread names instead of bare IDs)
- Link media -> multimodal: text-batch URL fetches that resolve to
  images now run vision analysis (bounded 15s) and switch prompt to
  mixed mode; <web_content> gains og:title for page context
- pnpm-workspace.yaml: approve sharp build script (unblocks install)

services/discord-gateway/src/modules/ai-moderation/mediaDownloader.ts

@@ -494,8 +494,9 @@ export async function fetchUrlInline(
       sourceLabel: `[gambar dari URL ${url} (inline), pesan id=${targetId}]`,
     });
   } else if (result.type === "text" && result.textContent) {
+    const titleAttr = result.title ? ` title="${escapeXml(result.title)}"` : "";
     webTexts.push(
-      `<web_content url="${escapeXml(url)}">${escapeXml(result.textContent.slice(0, 2000))}</web_content>`,
+      `<web_content url="${escapeXml(url)}"${titleAttr}>${escapeXml(result.textContent.slice(0, 2000))}</web_content>`,
     );
   }
 }