issue: #43107
pr: #43108
- Add checkLoadConfigChanges() to apply load config during startup
- Call config check in startQueryCoord() after restart
- Skip auto-updates for collections with user-specified replica numbers
- Add is_user_specified_replica_mode field to preserve user settings
- Add comprehensive unit tests with mockey
Ensures existing collections use latest cluster-level config after
restart.
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Signed-off-by: Wei Liu <wei.liu@zilliz.com>