fix: preserve reconnect attempt counter on second stream disconnect

When the SSE stream ends a second time without a response, the reconnect
attempt counter was incorrectly reset to 0, causing infinite reconnect
loops instead of properly backing off. Pass `attempt + 1` so the counter
advances correctly.

Author: enjoykumawat

src/mcp/client/streamable_http.py

@@ -421,9 +421,9 @@ async def _handle_reconnection(
                         await event_source.response.aclose()
                         return
 
-                # Stream ended again without response - reconnect again (reset attempt counter)
+                # Stream ended again without response - reconnect again
                 logger.info("SSE stream disconnected, reconnecting...")
-                await self._handle_reconnection(ctx, reconnect_last_event_id, reconnect_retry_ms, 0)
+                await self._handle_reconnection(ctx, reconnect_last_event_id, reconnect_retry_ms, attempt + 1)
         except Exception as e:  # pragma: no cover
             logger.debug(f"Reconnection failed: {e}")
             # Try to reconnect again if we still have an event ID