feat(solana-wallet-snap): use shareable state management lib

[Julink-eth]

Explanation

• Switch Solana to the shared @metamask/snap-networks-utils state helpers (IStateManager, State, InMemoryState) from #288
• Delete the local State / IStateManager / InMemoryState implementations and drop the now-unused async-mutex dependency.
• Keep Solana-only state shape in stateTypes.ts (UnencryptedStateValue / DEFAULT_UNENCRYPTED_STATE).
• Keep the legacy assets purge outside the shared class: registerStateMigration still runs on onStart / onUpdate / onInstall (old State constructor behavior). That key was replaced by assetEntities; existing installs still need the cleanup.
• Delete-account now uses one deleteKeys() call instead of three parallel deleteKey()s.

Not client-breaking: JSON-RPC surface and persisted state format are unchanged. deleteKey now unsets the path (same as Tron/Stellar and Solana’s old test double) instead of writing serialized undefined.

References

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've communicated my changes to consumers by updating changelogs for packages I've changed
• I've introduced breaking changes in this PR and have prepared draft pull requests for clients and consumer packages to resolve them

[Julink-eth]

@metamaskbot publish-preview

[github-actions]

Preview builds have been published. Learn how to use preview builds in other projects.

Expand for full list of packages and versions.

@metamask-previews/bitcoin-wallet-snap@2.0.1-preview-d6a148d0
@metamask-previews/snap-networks-utils@1.0.0-preview-d6a148d0
@metamask-previews/solana-wallet-snap@6.0.0-preview-d6a148d0
@metamask-previews/stellar-wallet-snap@0.1.0-preview-d6a148d0
@metamask-previews/tron-wallet-snap@3.2.0-preview-d6a148d0

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud