#25470 Refactor store interfaces to support generic value types (object stores):
Replace BasicKVStore, KVStore, and Iterator interfaces/types with generic GBasicKVStore[V], GKVStore[V], and GIterator[V]. The old names are retained as type aliases (e.g. KVStore = GKVStore[[]byte]).
Remove Iterator as a direct alias to dbm.Iterator. It is now GIterator[[]byte], a distinct interface defined in the store package. Code that type-asserts to dbm.Iterator will break.
Remove CacheWrap() and CacheWrapWithTrace() method declarations from the CacheWrap interface. CacheWrap now embeds CacheWrapper to obtain CacheWrap().
Add GetObjKVStore(StoreKey) ObjKVStore to the MultiStore interface.
Add generic store variants across cachekv, gaskv, prefix, transient, and mem packages (GStore[V], NewGStore, NewObjStore).
#26037 Remove GetCommitStore and GetCommitKVStore from the CommitMultiStore interface. Remove top-level store.CommitStore and store.CommitKVStore type aliases from store/reexport.go.
#26060 Remove non-functional StoreMetrics. This metric interface never worked, so this simply removes dead code.
#26061 Remove tracing from store interfaces and implementations:
Remove SetTracer, SetTracingContext, and TracingEnabled from MultiStore interface.
Remove CacheWrapWithTrace from CacheWrapper interface.
Remove traceWriter and traceContext parameters from cachemulti.NewStore, cachemulti.NewFromKVStore, and cachemulti.NewFromParent.
Remove store/tracekv package entirely.
Remove TraceContext type store/types.
Features
#25470 Add object KV stores and refactor the base store to be generic across the value parameter:
Add object store types: ObjKVStore, ObjBasicKVStore, ObjIterator, ObjectStoreKey, StoreTypeObject.
Add generic store types: GBasicKVStore[V], GKVStore[V], GIterator[V].
Add cachemulti.NewFromParent constructor for lazy cache multistore construction from a parent store function.
#25647 Add EarliestVersion() int64 to the CommitMultiStore interface and GetEarliestVersion(db) helper.
Bug Fixes
#20425 Fix nil pointer panic when querying historical state where a new store does not exist.
#24583 Fix pruning height calculation to correctly handle in-flight snapshots. Adds SnapshotAnnouncer interface and AnnounceSnapshotHeight to track snapshots in progress and prevent premature pruning of their heights.
