fix(grpc): return actual earliest_store_height in node.Status endpoint (backport #25647)

[mergify]

Description

Closes: #15463

Add EarliestVersion() to the CommitMultiStore interface to enable querying the earliest available state height.
This addresses the longstanding TODO in the Status gRPC endpoint that was returning 0 for EarliestStoreHeight.

Problem

Indexers and tooling need to know which heights a pruned node can serve queries for. Currently:

• earliest_block_height in CometBFT's STATUS RPC returns the earliest block, not the earliest state
• The EarliestStoreHeight field in cosmos.base.node.v1beta1.Status was hardcoded to 0

Solution

• Add EarliestVersion() int64 to the CommitMultiStore interface (not MultiStore, since CacheMultiStore lacks root DB access)
• Implement persistent tracking in rootmulti.Store:
  • Stores earliest version at s/earliest key
  • Defaults to 1 for unpruned chains
  • Updates after successful pruning in PruneStores()
• Add EarliestStoreHeight() and WithEarliestStoreHeight() to sdk.Context
• Populate earliestStoreHeight in query context creation (CreateQueryContextWithCheckHeader)
• Node gRPC service reads from context rather than storing a reference to the multistore

Changes

File	Change
store/types/store.go	Add EarliestVersion() to CommitMultiStore interface
store/rootmulti/store.go	Implement EarliestVersion(), GetEarliestVersion(), flushEarliestVersion(), update PruneStores()
store/rootmulti/store_test.go	Add 3 unit tests
types/context.go	Add earliestStoreHeight field with getter/setter
baseapp/abci.go	Populate earliestStoreHeight when creating query context
client/grpc/node/service.go	Read EarliestStoreHeight from context
runtime/app.go	Simplified service registration (no store param)
simapp/app.go	Simplified service registration (no store param)

Testing

• TestEarliestVersion - basic functionality, default value
• TestEarliestVersionWithPruning - tracks updates after pruning
• TestEarliestVersionPersistence - persists across restarts
• System test: TestNodeStatus - gRPC endpoint returns valid heights

API Changes

Breaking change for any code implementing CommitMultiStore — must now implement EarliestVersion() int64.
No impact on MultiStore or CacheMultiStore implementations.

---

This is an automatic backport of pull request #25647 done by Mergify.

[mergify]

Cherry-pick of ae80efb has failed:

On branch mergify/bp/release/v0.53.x/pr-25647
Your branch is up to date with 'origin/release/v0.53.x'.

You are currently cherry-picking commit ae80efbfd.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   client/grpc/node/service.go
	modified:   client/grpc/node/service_test.go
	modified:   runtime/app.go
	modified:   server/mock/store.go
	modified:   simapp/app.go
	modified:   store/rootmulti/store_test.go
	modified:   store/types/store.go
	new file:   tests/systemtests/node_service_test.go

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	both modified:   CHANGELOG.md
	deleted by us:   enterprise/poa/simapp/app.go
	both modified:   store/rootmulti/store.go

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[technicallyty]

@Cordtus unfortunately i won't be able to backport this one, as it would require a bump to store. this one is only going to be supported in future releases