fix(heal): retain hints without verified repair receipts (#7275)

Stop task completion and legacy notices from discharging scanner retry hints. Preserve existing hints and their retry due time across admission observations, bound retry scheduling, and synchronize changed batches once even on cancellation.

Exercise the production MRF consumer, manager, event channel and scanner ledger. Document producer durability gaps without enabling successor activation or garbage collection.

Co-authored-by: heihutu <heihutu@gmail.com>
Co-authored-by: zhi22915 <qiuzgang@gmail.com>

crates/scanner/src/storage_api.rs

@@ -126,6 +126,9 @@ pub(crate) use rustfs_lifecycle::{
 };
 use rustfs_storage_api as storage_contracts;
 
+#[cfg(test)]
+pub(crate) type EcstoreHealResultItem = <EcstoreStore as storage_contracts::HealOperations>::HealResultItem;
+
 pub(crate) mod owner {
     #[cfg(test)]
     pub(crate) use rustfs_ecstore::api::set_disk::test_util::hold_namespace_commit as ecstore_hold_namespace_commit;