Upgrade @parity/product-sdk and dependencies to the latest releases

Summary

Bring the @parity/product-sdk packages up to the latest releases. This repo is the furthest behind, so the upgrade is substantial.

Current versions

• @parity/product-sdk-host ^0.8.0
• @parity/product-sdk-signer ^0.6.3

Target versions (latest)

• @parity/product-sdk-host 0.14.1
• @parity/product-sdk-signer 0.11.1
• Add and pin the other @parity/product-sdk-* packages the quests use (chain-client 0.9.1, contracts 0.9.2, descriptors 0.8.0, tx 0.3.2) as needed.

Breaking changes to plan for

• The host and signer API surfaces changed across many minor releases between 0.8 and 0.14.
• @parity/product-sdk@0.18.0 introduced the Result based error API, replacing throws in submitAndWatch, contract .tx / .prepare, and cloud storage queryJson.

Because of the size of the jump, do this in steps and lean on the truAPI transport switch that this upgrade depends on.

What needs to happen

• Step the host and signer up to the target versions, resolving breaking changes at each stage.
• Adopt the Result error API across the quest code.
• Bump polkadot-api and the transitive @polkadot-api/* packages.
• Re-run every quest end to end.

Acceptance criteria

• The tutorial builds and typechecks on the new versions.
• Every quest completes against the host.
• Any tutorial smoke test passes.

Start with the quest code and the truAPI transport switch described in the issue. Upgrade the host, signer, and other @parity/product-sdk-* packages in stages, resolving the listed API changes as they appear. Run the tutorial typecheck, smoke test, and every quest end to end; done means all quests complete against the host.