[ENHANCEMENT] Add k6 or Artillery load testing for critical API paths

[kilodesodiq-arch]

Engineering Gap

No load testing or performance benchmarking infrastructure. Unknown throughput limits, concurrency behavior, or bottleneck locations.

Codebase Evidence

• No tests/load/ directory
• No k6, Artillery, or Locust scripts
• CI runs unit and e2e tests only

Risk Profile

Unknown performance under load. Crisis-scale aid distribution could overwhelm backend.

Remediation Strategy

Add k6 scripts for: campaign creation, claim submission, evidence upload, aid package listing. Add as optional CI workflow_dispatch job. Document limits.

Success Conditions

• k6 scripts for critical paths
• Optional CI job
• Performance limits documented

Change Surface

New: tests/load/, .github/workflows/load-test.yml

Security Review

No security impact.

Completion Checklist

• Implementation completed
• CI job working
• Ready for merge

[xx7412421-cloud]

I'd like to take this on if assignment is available. I can keep the change scoped to optional k6 load scripts, a manual workflow, and lightweight documentation.