v3.8.3-patch.15

What's Changed

fix: group notification by @icey-yu in https://github.com/openimsdk/open-im-server/pull/3619
fix: resolve deadlock in cache eviction and improve GetBatch implementation by @withchao in https://github.com/openimsdk/open-im-server/pull/3638
feat: replace LongConn with ClientConn interface and simplify message handling by @withchao in https://github.com/openimsdk/open-im-server/pull/3645
Fix/group member rejoin bug 3.8.3 by @zhouribin in https://github.com/openimsdk/open-im-server/pull/3646
refactor: simplify platformID handling and enhance UserConnContext structure by @withchao in https://github.com/openimsdk/open-im-server/pull/3648
fix(group): set max_seq to 0 when join group by @dsx137 in https://github.com/openimsdk/open-im-server/pull/3647

@dsx137 made their first contribution in https://github.com/openimsdk/open-im-server/pull/3647

Full Changelog: https://github.com/openimsdk/open-im-server/compare/v3.8.3-patch.12...v3.8.3-patch.15