feat: support new model Grok 4.20 Beta

# Conflicts:
#	app/services/grok/services/chat.py

scripts/test_usage_response.py

@@ -0,0 +1,62 @@
+"""
+Simple usage probe to inspect /rest/rate-limits response.
+
+Usage:
+  python scripts/test_usage_response.py
+  (optional) TOKEN_POOL=ssoBasic|ssoSuper
+"""
+
+import asyncio
+import os
+import sys
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[1]
+if str(ROOT) not in sys.path:
+    sys.path.insert(0, str(ROOT))
+
+from curl_cffi.requests import AsyncSession
+
+from app.core.config import config
+from app.services.reverse.rate_limits import RateLimitsReverse
+from app.services.token import get_token_manager
+
+
+async def main() -> int:
+    await config.load()
+    token = None
+    pool = os.getenv("TOKEN_POOL")
+    manager = await get_token_manager()
+    await manager.reload_if_stale()
+
+    if pool:
+        token = manager.get_token(pool_name=pool)
+    else:
+        token = manager.get_token(pool_name="ssoBasic") or manager.get_token(
+            pool_name="ssoSuper"
+        )
+
+    if not token:
+        token = os.getenv("GROK_TOKEN") or os.getenv("SSO_TOKEN") or os.getenv("TOKEN")
+    if not token:
+        print("Missing token. Ensure token pool is configured or set GROK_TOKEN.")
+        return 2
+
+    async with AsyncSession() as session:
+        response = await RateLimitsReverse.request(session, token)
+
+    try:
+        data = response.json()
+    except Exception as exc:
+        print(f"Failed to parse JSON: {exc}")
+        raw = getattr(response, "text", "")
+        if raw:
+            print(raw)
+        return 3
+
+    print(data)
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(asyncio.run(main()))