[GPCAPIM-285] JWT creation

[Vox-Ben]

Description

This adds code for creating a JWT and passing it to the GP provider with the request. Note that at present we aren't sure how some fields will be obtained, so they're hard-coded to placeholder values for the time being.

Context

It is a requirement to pass a JWT to the provider for auditing purposes. This fulfils that requirement.

Type of changes

• Refactoring (non-breaking change)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would change existing functionality)
• Bug fix (non-breaking change which fixes an issue)

Checklist

• I have followed the code style of the project
• I have added tests to cover my changes
• I have updated the documentation accordingly
• This PR is a result of pair or mob programming
• Exceptions/Exclusions to coding standards (e.g. #noqa or #NOSONAR) are included within this Pull Request.

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Sensitive Information Declaration

To ensure the utmost confidentiality and protect your and others privacy, we kindly ask you to NOT including PII (Personal Identifiable Information) / PID (Personal Identifiable Data) or any other sensitive data in this PR (Pull Request) and the codebase changes. We will remove any PR that do contain any sensitive information. We really appreciate your cooperation in this matter.

• I confirm that neither PII/PID nor sensitive data are included in this PR and the codebase changes.

[github-actions]

✅ Trivy gate: no Critical/High issues.

Trivy IaC (Terraform) Summary

Severity	Count
CRITICAL	0
HIGH	0
MEDIUM	0
LOW	0
UNKNOWN	0

Findings (top 50)

Severity	ID	Title	File

[github-actions]

✅ Trivy gate: no Critical/High vulnerabilities.

Trivy Image Scan Summary

Image: 900119715266.dkr.ecr.eu-west-2.amazonaws.com/whoami:feature-gpcapim-285-jwt

Severity	Count
CRITICAL	0
HIGH	0
MEDIUM	0
LOW	1
UNKNOWN	0

Findings (top 50)

Severity	ID	Package	Installed	Fixed	Source
LOW	CVE-2026-1703	pip	25.3	26.0	Python

[davidhamill1-nhs]

Looks good.

A few comments, but mostly superficial or my out-loud thoughts.

[sonarqubecloud]

Quality Gate passed

Issues
4 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

[github-actions]

Deployment Complete

• Preview URL: https://feature-gpcapim-285-jwt.dev.endpoints.clinical-data-gateway.national.nhs.uk — Health endpoint
  • Smoke Test: ✅ Passed (HTTP 200)
• Proxy URL: https://internal-dev.api.service.nhs.uk/clinical-data-gateway-api-poc-pr-88
• ECS Cluster: ecs-cluster
• ECS Service: pr-feature-gpcapim-285-jwt
• ALB Target: arn:aws:elasticloadbalancing:eu-west-2:900119715266:targetgroup/gpcapim-285-jwt/d7fe28d025dd010b