Feature/typescript didclient vc methods

[Luffy2208]

Summary

Adds verifyCredential, getWorkflowVcChain, and createWorkflowVc to the TypeScript DidClient, aligned with the Python VCGenerator API and behavior.

Also adds unit tests for the new DID client methods and extends integration (E2E) tests to cover the full VC flow through the SDK (generation, aggregation, retrieval, and verification).

Testing

• ./scripts/test-all.sh
• Additional verification:

cd sdk/typescript && npm test -- tests/did_client_methods.test.ts tests/integration.e2e.test.ts
cd sdk/typescript && npm run lint

Unit tests (did_client_methods.test.ts):

• verifies credentials with the raw verifier payload
• verifies credential without detached signature
• gets the raw workflow VC chain response
• creates a workflow VC from workflow metadata and execution VC ids

Integration tests (integration.e2e.test.ts):

• registers DID identities and issues workflow VCs through ctx.did during live executions

Checklist

• I updated documentation where applicable.
• I added or updated tests (or none were needed).
• I updated CHANGELOG.md (or this change does not warrant a changelog entry).

Screenshots (if UI-related)

N/A

Related issues

Fixes #92

[github-actions]

Performance

SDK	Memory	Δ	Latency	Δ	Tests	Status
TS	236 B	-33%	3.75 µs	+88%	✓	✗

✓ No regressions detected

[github-actions]

📊 Coverage gate

Thresholds from .coverage-gate.toml: per-surface ≥ 86%, aggregate ≥ 88%, max per-surface regression ≤ 1.0 pp, max aggregate regression ≤ 0.50 pp.

Surface	Current	Baseline	Δ
control-plane	87.20%	87.30%	↓ -0.10 pp	🟡
sdk-go	90.70%	90.70%	→ +0.00 pp	🟢
sdk-python	93.63%	93.63%	↑ +0.00 pp	🟢
sdk-typescript	92.62%	92.56%	↑ +0.06 pp	🟢
web-ui	90.02%	90.01%	↑ +0.01 pp	🟢
aggregate	88.98%	89.01%	↓ -0.03 pp	🟡

✅ Gate passed

No surface regressed past the allowed threshold and the aggregate stayed above the floor.

[github-actions]

📐 Patch coverage gate

Threshold: 80% on lines this PR touches vs origin/main (from .coverage-gate.toml:thresholds.min_patch).

Surface	Touched lines	Patch coverage	Status
control-plane	0	—	➖ no changes
sdk-go	0	—	➖ no changes
sdk-python	0	—	➖ no changes
sdk-typescript	47	100.00%	✅
web-ui	0	—	➖ no changes

✅ Patch gate passed

Every surface whose lines were touched by this PR has patch coverage at or above the threshold.