Upgrade Credo from 0.5.19 to 0.6.2

[Copilot]

Upgrades all Credo-related dependencies to 0.6.2 and adapts to breaking API changes in the 0.6.x release line. Also moves from askar-nodejs 0.4.3 (native ffi-napi bindings) to 0.6.0 (koffi-based), resolving Node 24 compilation failures.

Dependency changes (backend/package.json)

• @credo-ts/core, @credo-ts/node, @credo-ts/askar: 0.5.19 → 0.6.2
• @openwallet-foundation/askar-nodejs: 0.4.3 → 0.6.0
• Added @openwallet-foundation/askar-shared: 0.6.0 override to unify the two copies npm would otherwise install (credo-ts/askar peers ^0.4.3, askar-nodejs bundles 0.6.0)

Agent initialization (credoAgent.ts)

Wallet configuration moved from InitConfig.walletConfig into AskarModule.store:

// Before (0.5.x)
new Agent({
  config: { label: '...', walletConfig: { id, key, keyDerivationMethod: KeyDerivationMethod.Argon2IInt, storage } },
  modules: { askar: new AskarModule({ ariesAskar: askar }) },
});

// After (0.6.x)
new Agent({
  dependencies: agentDependencies,
  modules: {
    askar: new AskarModule({
      askar,
      store: { id, key, keyDerivationMethod: 'kdf:argon2i:int', database },
    }),
  },
});

• KeyType.P256 → createKey: { type: { kty: 'EC', crv: 'P-256' } } (new KMS API)
• AskarWalletPostgresStorageConfig → AskarPostgresStorageConfig
• InitConfig, KeyDerivationMethod, WalletStorageConfig imports removed (no longer exported)

SD-JWT VC issuance (employeeCredentialService.ts)

• Default headerType changed from vc+sd-jwt to dc+sd-jwt in 0.6.2 — explicitly set headerType: 'vc+sd-jwt' for backward compatibility
• Payload typed as { vct: string } & Record<string, unknown> to satisfy new SdJwtVcPayload constraint

Tests

No test changes required — all 25 existing tests pass as-is since mocks align with the unchanged agent.sdJwtVc.sign() surface.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Upgrade Credo from 0.5.19 to 0.6.2 (dependency, API, and storage changes)</issue_title>
<issue_description>## Overview
Upgrade all Credo-related dependencies from version 0.5.19 to 0.6.2. This includes updating @credo-ts/core, @credo-ts/node, @credo-ts/askar, and @openwallet-foundation/askar-nodejs. The upgrade involves breaking changes that may affect agent initialization, storage, APIs, and the SD-JWT VC flow. Follow the official Credo migration guide and release notes for 0.6.x.

Link this issue to the relevant project board for end-to-end visibility.

Definition of Ready (DoR)

• Clear understanding of breaking changes in Credo 0.6.x
• Update Assistant reviewed for all migration steps
• All referenced code locations identified (see below)
• All project stakeholders notified of potential breaking changes
• Current system and storage are backed up

Tasks

• Update backend/package.json dependencies:
  • @credo-ts/core: 0.6.2
  • @credo-ts/node: 0.6.2
  • @credo-ts/askar: 0.6.2
  • @openwallet-foundation/askar-nodejs: latest compatible version
• Re-run npm install / npm update
• Update all imports and usage in backend/src/agent/credoAgent.ts to reflect API changes
  • e.g., Agent initialization, storage configuration, any changed or removed APIs
  • File reference: backend/src/agent/credoAgent.ts
• Update issuance flow in backend/src/services/employeeCredentialService.ts for SD-JWT VC as needed
  • File reference: backend/src/services/employeeCredentialService.ts
• Update/fix tests and mocks if APIs or interfaces have changed
  • Directory reference: backend/src/__tests__/
• If storage (wallet) migration is required (see migration guide), apply accordingly
• Update documentation as needed for environment or configuration changes
• Regenerate package-lock.json

Definition of Done (DoD)

• All package references updated to Credo 0.6.2
• All breaking API, storage, or config changes resolved and tested
• Existing credential issuing and verification flows work as before (manual or automated test)
• npm run build and npm test both succeed with 0.6.2
• All tests pass or are updated for 0.6.x
• No deprecated modules (e.g. Indy SDK) referenced
• Documentation is up to date

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Code references

• backend/package.json: dependency versions
• backend/src/agent/credoAgent.ts: agent initialization, wallet usage
• backend/src/services/employeeCredentialService.ts: VC issuance using Credo SD-JWT
• backend/src/__tests__/: test code

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Created by Paula (bots branch instructions) to fulfill [AC-0013].</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Upgrade Credo from 0.5.19 to 0.6.2 (dependency, API, and storage changes) #42

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