feat: parallelize lookup (Wiki+SearXNG) and include Wikipedia thumbnails

Runs the Wikipedia summary and SearXNG search concurrently and returns
both when available, so current-event questions aren't masked by a
generic role article from Wikipedia. When the Wikipedia summary includes
a thumbnail, it is cached through the existing image pipeline and
surfaced as an embeddable markdown snippet alongside the extract.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/fabledassistant/services/wikipedia.py

@@ -12,11 +12,21 @@ _TIMEOUT = 5.0
 _USER_AGENT = "FabledAssistant/1.0 (https://fabledsword.com)"
 
 
+def _extract_thumbnail(data: dict) -> str:
+    """Prefer the 320px thumbnail (kinder to cache/bandwidth) over originalimage."""
+    thumb = data.get("thumbnail", {}).get("source", "")
+    if thumb:
+        return thumb
+    return data.get("originalimage", {}).get("source", "")
+
+
 async def wiki_summary(query: str) -> dict | None:
     """Fetch a Wikipedia summary for a given title/query.
 
     Does a direct title lookup via the REST v1 summary endpoint.
-    Returns a dict with title, extract, and url on success; None on any failure.
+    Returns a dict with title, extract, url, and thumbnail_url on success;
+    thumbnail_url is an empty string when the article has no image.
+    Returns None on any failure.
     """
     title = url_quote(query.replace(" ", "_"))
     url = f"{_SUMMARY_URL}/{title}"
@@ -37,6 +47,7 @@ async def wiki_summary(query: str) -> dict | None:
                 "title": data.get("title", query),
                 "extract": extract,
                 "url": data.get("content_urls", {}).get("desktop", {}).get("page", ""),
+                "thumbnail_url": _extract_thumbnail(data),
             }
     except Exception as exc:
         logger.debug("wiki_summary failed for %r: %s", query, exc)
@@ -91,6 +102,7 @@ async def wiki_search(query: str, limit: int = 3) -> list[dict]:
                             "url": sdata.get("content_urls", {})
                             .get("desktop", {})
                             .get("page", ""),
+                            "thumbnail_url": _extract_thumbnail(sdata),
                         }
                     )
                 except Exception as exc: