fix: refactor DID:web key generation to use agent wallet

[rmlearney-digicatapult]

Pull Request

Checklist

• Have you read Digital Catapult's Code of Conduct?
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation.
• My changes generate no new warnings.
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally with my changes.

PR Type

Please delete options that are irrelevant.

• Feature

Linked tickets

High level description

Generate signing keys from agent's wallet to remove dependency on ts-jose and back-importing of generated keys

Detailed description

AI-assisted change to generate DID document's signing keys from agent wallet for guaranteed storage in the agent, enhanced privacy (keys not calculated or stored in memory, private keys not exposed), and reduced complexity by removing helper methods.

Refactored to in-line did document import method after generation.

Enhanced unit test for signing key and encryption key verification.

Use credo-ts native filtering for did lookup.

Describe alternatives you've considered

Operational impact

No functional changes

Additional context

[Copilot]

Pull request overview

This PR refactors DID:web key generation to use the Credo TS agent's wallet for key creation and storage, removing the dependency on the ts-jose library. The change enhances security by ensuring keys are generated and stored directly in the agent's secure wallet rather than being temporarily held in memory.

Key Changes:

• Generate signing and encryption keys directly through the agent's wallet API instead of using ts-jose
• Remove the need to import private keys after generation since they're already stored in the wallet
• Eliminate the extractKeyComponents helper method and related private key handling code

Reviewed changes

Copilot reviewed 2 out of 3 changed files in this pull request and generated 2 comments.

File	Description
src/utils/didWebGenerator.ts	Refactored to use agent.wallet.createKey() for key generation, removed ts-jose imports and helper methods, simplified importDidWeb() to no longer pass privateKeys
package.json	Removed ts-jose dependency and bumped version to 0.16.15