replace deleted SDK alias SealedHeader and bump version

[Fraser999]

Summary

• Bump all storage crates from 0.7.2 to 0.8.0
• Upgrade signet-sdk dependencies from 0.16.0-rc.11 to 0.17.1
• Provide SealedHeader as a local type alias (Sealed<Header>) in signet-storage-types instead of re-exporting from signet-types, which no longer exports it

Motivation

signet-sdk 0.17.1 (init4tech/signet-sdk#232) removes the SealedHeader type alias from signet_types::primitives in favour of the validated SignetHeaderV1/SignetHeaderV2 wrapper types. Storage doesn't need the signet-specific header validation - it stores plain alloy::consensus::Header values - so we define the same Sealed<Header> alias locally and keep the rest of the codebase unchanged.

Note

The PR will only pass CI once init4tech/signet-sdk#232 is merged and the new version published.

Test plan

• cargo t --workspace - all tests pass
• cargo clippy --workspace --all-targets --all-features
• cargo clippy --workspace --all-targets --no-default-features
• RUSTDOCFLAGS="-D warnings" cargo doc --workspace --no-deps

[Fraser999]

• replace deleted SDK alias SealedHeader and bump version #61 👈 (View in Graphite)
• main

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[prestwich]

approval for concept ACK