fix(msk): isolate MSK resources by account and region

[nkootstra]

Summary

MSK broker logs and legacy host-persistent storage are now isolated by AWS account and region. This prevents resources with the same cluster name in different environments from sharing log streams or data directories.

Type of change

• Bug fix (fix:)
• New feature (feat:)
• Breaking change (feat!: or fix!:)
• Docs / chore

AWS Compatibility

MSK cluster identity includes the account and region. Floci now uses that identity when attaching broker logs and constructing the legacy host storage path, while preserving the existing cluster name in user-facing log labels and container labels.

Checklist

• ./mvnw test passes locally
• New or updated integration test added
• Commit messages follow Conventional Commits

[github-actions]

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[greptile-apps]

Greptile Summary

This PR isolates MSK resources by AWS account and region while retaining compatibility with persisted legacy clusters.

• Builds new cluster ARNs from the request region and persists that region with each cluster.
• Limits cluster discovery and operations to the current region while keeping unmarked legacy records accessible.
• Uses account-and-region-aware identities for broker logs, container labels, and host storage paths.
• Preserves legacy host-path data only for clusters that predate the regional marker.
• Adds regression coverage for regional isolation and legacy storage compatibility.

Confidence Score: 5/5

The PR appears safe to merge, with all previous findings resolved and no new actionable issues introduced since the previous review.

The current implementation preserves legacy cluster visibility and broker data while ensuring newly created clusters use account-and-region-scoped identities. The legacy fallback is limited to records without the persisted region marker, so new same-name clusters cannot reuse legacy storage across environments.

Important Files Changed

Filename	Overview
src/main/java/io/github/hectorvent/floci/services/msk/MskService.java	Persists request-region identity and applies compatible regional filtering to MSK operations.
src/main/java/io/github/hectorvent/floci/services/msk/RedpandaManager.java	Isolates log streams, labels, and host storage by cluster account and region while preserving legacy data access.
src/main/java/io/github/hectorvent/floci/services/msk/model/MskCluster.java	Adds the persisted resource-region marker used to distinguish scoped clusters from legacy records.
src/test/java/io/github/hectorvent/floci/services/msk/MskServiceTest.java	Covers same-name regional clusters, cross-region access restrictions, and legacy record visibility.
src/test/java/io/github/hectorvent/floci/services/msk/RedpandaManagerTest.java	Covers account-aware logging, scoped host paths, and guarded legacy path reuse.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    Request[MSK request] --> Context[Resolve account and region]
    Context --> Cluster[Create or select cluster]
    Cluster --> ARN[Account and region scoped ARN]
    ARN --> Logs[Account and region scoped broker logs]
    ARN --> Storage{Legacy record?}
    Storage -->|No| Scoped[Scoped host data path]
    Storage -->|Yes and legacy path exists| Legacy[Legacy cluster-name path]
    Storage -->|Yes and legacy path absent| Scoped

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_{Reviews (4): Last reviewed commit: "ci: retrigger PR checks after unrelated ..." | Re-trigger Greptile}

[pgermosen]

Traced this against the existing account-scoping mechanism rather than assuming it duplicates it: cluster metadata already gets that for free from AccountAwareStorageBackend, so the real gap closed here is region on the metadata side and both account+region on the RedpandaManager log/host-path side. Deriving region and account from the cluster's own ARN rather than live request context is the right call for a background lifecycle thread. The legacy-record fallback is explicitly reasoned in a comment, not an oversight. Approving.