Merge PR #48: feat: add Xiaohongshu source + Reddit public fallback

- Xiaohongshu search via local MCP service (opt-in, zero impact if service not running)
- Reddit public JSON fallback (works with zero API keys)
- Reddit priority: ScrapeCreators -> OpenAI -> public fallback
- Updated env.py: Reddit always available via public fallback

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

vendor/package/dist/lib/extract-list-id.js

@@ -0,0 +1,19 @@
+// ABOUTME: Extract list ID from an X/Twitter list URL.
+// ABOUTME: Returns list ID or null if input is invalid.
+const LIST_URL_REGEX = /(?:twitter\.com|x\.com)\/i\/lists\/(\d+)/i;
+const LIST_ID_REGEX = /^\d{5,}$/;
+export function extractListId(input) {
+    const trimmed = input.trim();
+    if (!trimmed) {
+        return null;
+    }
+    const urlMatch = LIST_URL_REGEX.exec(trimmed);
+    if (urlMatch) {
+        return urlMatch[1];
+    }
+    if (LIST_ID_REGEX.test(trimmed)) {
+        return trimmed;
+    }
+    return null;
+}
+//# sourceMappingURL=extract-list-id.js.map