feat(shared): extractUrls helper for multi-embed message parsing (P666)

Export extractUrls up to N unique http(s) URLs; extractFirstUrl delegates
to first entry for backward-compatible unfurl policy.

Co-authored-by: Cursor <[email protected]>

format-message.js

@@ -63,8 +63,25 @@ function extractMentionNames (content) {
 }
 
 function extractFirstUrl (content) {
-  const m = String(content ?? '').match(URL_RE)
-  return m ? m[0] : null
+  const urls = extractUrls(content, 1)
+  return urls[0] || null
+}
+
+/** Up to `maxCount` unique http(s) URLs in message order (Phase 666). */
+function extractUrls (content, maxCount = 3) {
+  const cap = Math.max(1, Math.min(Number(maxCount) || 3, 10))
+  const seen = new Set()
+  const out = []
+  const re = new RegExp(URL_RE.source, URL_RE.flags)
+  let m
+  while ((m = re.exec(String(content ?? ''))) && out.length < cap) {
+    const url = m[0]
+    if (!seen.has(url)) {
+      seen.add(url)
+      out.push(url)
+    }
+  }
+  return out
 }
 
 /** Local link card metadata (no network fetch — P2P-safe). */
@@ -120,6 +137,7 @@ module.exports = {
   formatMessageContent,
   extractMentionNames,
   extractFirstUrl,
+  extractUrls,
   linkPreviewMeta,
   buildLinkPreviewHtml,
   buildRichEmbedHtml,

index.js

@@ -642,6 +642,7 @@ const {
   formatMessageContent,
   extractMentionNames,
   extractFirstUrl,
+  extractUrls,
   linkPreviewMeta,
   buildLinkPreviewHtml,
   buildRichEmbedHtml,
@@ -734,6 +735,7 @@ module.exports = {
   formatMessageContent,
   extractMentionNames,
   extractFirstUrl,
+  extractUrls,
   linkPreviewMeta,
   buildLinkPreviewHtml,
   buildRichEmbedHtml,