chore: remove dead storage-challenge and health-check Hash helpers

[j-rafique]

Drops 7 unreachable functions flagged by deadcode -test ./...:

pkg/types/storage_challenge.go
- MessageTypeFromString
- (StorageChallengeMessages).Hash + the orphan slice type
- (AggregatedScoreList).Hash + the orphan slice type pkg/types/healthcheck_challenge.go
- (HealthCheckChallengeMessages).Hash + the orphan slice type
pkg/utils/storagechallenge/storage_challenge.go (whole pkg, orphan)
pkg/utils/healthcheckchallenge/health_check_challenge.go (whole pkg, orphan)
pkg/storagechallenge/deterministic/deterministic.go
- EpochStartHeight

Verified via deadcode diff on origin/master @ 82cebf7: baseline 147 ->
after 140 (exactly the 7 above removed, no new findings). MessageType, HealthCheckMessage and the consumed deterministic helpers stay.

go build ./..., go vet ./..., and go test ./... -short -count=1 pass in the supernode module; sn-manager, cmd/sncli, and tests/system also build clean.

[Copilot]

Pull request overview

This PR removes dead/unreachable storage-challenge and health-check hashing/helper code paths that were flagged by deadcode -test ./..., reducing maintenance surface without changing live behavior.

Changes:

• Deleted orphaned pkg/utils/storagechallenge and pkg/utils/healthcheckchallenge summary-hash helpers.
• Removed unused hashing slice-types and MessageTypeFromString from pkg/types/*_challenge.go.
• Removed unused deterministic helper EpochStartHeight from pkg/storagechallenge/deterministic.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
pkg/utils/storagechallenge/storage_challenge.go	Removes unused summary stats hashing helper (entire file deleted).
pkg/utils/healthcheckchallenge/health_check_challenge.go	Removes unused summary stats hashing helper (entire file deleted).
pkg/types/storage_challenge.go	Drops unused message parsing + hash helper slice types and related imports.
pkg/types/healthcheck_challenge.go	Drops unused hash helper slice type and related imports.
pkg/storagechallenge/deterministic/deterministic.go	Removes unused EpochStartHeight helper.

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