feat: also parse markdown image links for Discord image sending

Support [name.png](/path) format in addition to [SendImage: /path].
LLMs naturally produce markdown links, so both patterns are recognized.
Only absolute paths with image extensions are matched.

src/channels/discord.ts

@@ -303,19 +303,35 @@ export class DiscordChannel implements Channel {
 
       const textChannel = channel as TextChannel;
 
-      // Extract image attachments from [SendImage: /path] tags
+      // Extract image attachments from agent responses.
+      // Supports:
+      //   [SendImage: /absolute/path]           — explicit tag
+      //   [name.png](/absolute/path/name.png)   — markdown link with image extension
+      const IMAGE_EXTS = /\.(png|jpe?g|gif|webp|svg|bmp)$/i;
       const SEND_IMAGE_RE = /\[SendImage:\s*(\/[^\]]+)\]/g;
+      const MD_LINK_RE = /\[[^\]]*\]\((\/[^)]+)\)/g;
       const imageFiles: string[] = [];
+      const seen = new Set<string>();
       let match;
+
       while ((match = SEND_IMAGE_RE.exec(text)) !== null) {
         const imgPath = match[1].trim();
-        if (fs.existsSync(imgPath)) {
+        if (!seen.has(imgPath) && fs.existsSync(imgPath)) {
           imageFiles.push(imgPath);
-        } else {
-          logger.warn({ path: imgPath }, 'SendImage file not found, skipping');
+          seen.add(imgPath);
         }
       }
-      let cleaned = text.replace(SEND_IMAGE_RE, '').trim();
+      while ((match = MD_LINK_RE.exec(text)) !== null) {
+        const imgPath = match[1].trim();
+        if (!seen.has(imgPath) && IMAGE_EXTS.test(imgPath) && fs.existsSync(imgPath)) {
+          imageFiles.push(imgPath);
+          seen.add(imgPath);
+        }
+      }
+      let cleaned = text
+        .replace(SEND_IMAGE_RE, '')
+        .replace(MD_LINK_RE, (full, p) => IMAGE_EXTS.test(p) && seen.has(p.trim()) ? '' : full)
+        .trim();
 
       // Convert @username mentions to Discord mention format
       const mentionMap: Record<string, string> = {