feat: add SearX search plugin and alert backend

Add standalone !searx command for on-demand SearXNG search (top 3 results).
Add SearX as a third backend (sx) to the alert plugin for keyword monitoring.

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

plugins/alert.py

@@ -26,6 +26,7 @@ _YT_SEARCH_URL = "https://www.youtube.com/youtubei/v1/search"
 _YT_CLIENT_VERSION = "2.20250101.00.00"
 _GQL_URL = "https://gql.twitch.tv/gql"
 _GQL_CLIENT_ID = "kimne78kx3ncx6brgo4mv6wki5h1ko"
+_SEARX_URL = "http://192.168.122.119:3000/search"
 
 # -- Module-level tracking ---------------------------------------------------
 
@@ -193,11 +194,40 @@ def _search_twitch(keyword: str) -> list[dict]:
     return results
 
 
+# -- SearXNG search (blocking) ----------------------------------------------
+
+def _search_searx(keyword: str) -> list[dict]:
+    """Search SearXNG. Blocking."""
+    import urllib.parse
+
+    params = urllib.parse.urlencode({"q": keyword, "format": "json"})
+    url = f"{_SEARX_URL}?{params}"
+
+    req = urllib.request.Request(url, method="GET")
+    resp = urllib.request.urlopen(req, timeout=_FETCH_TIMEOUT)
+    raw = resp.read()
+    resp.close()
+
+    data = json.loads(raw)
+    results: list[dict] = []
+    for item in data.get("results", []):
+        item_url = item.get("url", "")
+        title = item.get("title", "")
+        results.append({
+            "id": item_url,
+            "title": title,
+            "url": item_url,
+            "extra": "",
+        })
+    return results
+
+
 # -- Backend registry -------------------------------------------------------
 
 _BACKENDS: dict[str, callable] = {
     "yt": _search_youtube,
     "tw": _search_twitch,
+    "sx": _search_searx,
 }