fix: Increase WildFiles RAG timeout from 5s to 15s

Embedding generation on CPU (bge-m3) takes ~3s, plus network latency
can exceed 5s causing silent failures and empty results.

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

bot.py

@@ -85,7 +85,7 @@ class DocumentRAG:
         if not self.enabled:
             return []
         try:
-            async with httpx.AsyncClient(timeout=5.0) as client:
+            async with httpx.AsyncClient(timeout=15.0) as client:
                 resp = await client.post(
                     f"{self.base_url}/api/v1/rag/search",
                     json={"query": query, "organization": self.org, "limit": top_k},