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/normalize-handle.d.ts

@@ -0,0 +1,6 @@
+export declare function normalizeHandle(input?: string | null): string | null;
+export declare function mentionsQueryFromUserOption(userOption?: string | null): {
+    query: string | null;
+    error: string | null;
+};
+//# sourceMappingURL=normalize-handle.d.ts.map