fix: switch SearchTimeline from GET to POST

X started rejecting GET on SearchTimeline ~2026-05-10. Verified live
against 4 sessions (3 quarantined per the in-house streak counter,
1 fresh) × 3 queries each = 12 trials:

  GET (current twikit):  12/12 → 404 with content-length: 0
  POST (this PR):        12/12 → 200 with 130-180 KB of search results

The POST body is identical to what GET sent as URL-encoded params,
plus ``queryId`` (added automatically by ``gql_post``) and
``fieldToggles`` moved from ``extra_params`` to ``extra_data``.
Mirrors d60#412.

The "shadow flag" pattern we initially observed (~75% of accounts
404'ing) was an artifact of GET enforcement, not per-account
behaviour — POST works for every session.

Author: kasparasizi1

twikit/client/gql.py

@@ -195,14 +195,16 @@ async def search_timeline(
         }
         if cursor is not None:
             variables['cursor'] = cursor
-        params = {
-            'fieldToggles': {'withArticleRichContentState': False}
-        }
-        return await self.gql_get(
+        # X started rejecting GET on SearchTimeline ~2026-05-10 — every GET
+        # returns 404 with empty body across all account states (verified
+        # against quarantined + healthy sessions alike). POST with the same
+        # payload as JSON body returns 200 with full search results.
+        # Mirrors d60/twikit#412.
+        return await self.gql_post(
             Endpoint.SEARCH_TIMELINE,
             variables,
             SEARCH_TIMELINE_FEATURES,
-            extra_params=params,
+            extra_data={'fieldToggles': {'withArticleRichContentState': False}},
         )
 
     async def similar_posts(self, tweet_id: str):