Add Tests for Price Cache Warmup Job

[Mosas2000]

Description

The price cache warmup job has no tests. backend/src/jobs/priceCacheWarmup.job.ts has no corresponding file in backend/tests/jobs/ (only supplyVerification and verification jobs are tested), so price cache priming logic is untested.

Requirements and context

• Add a priceCacheWarmup.job.test.ts
• Cover cache priming, source aggregation, and failure handling
• Use existing job test conventions
• Ensure it runs under the unit vitest config

Suggested execution

Fork the repo and create a branch

git checkout -b test/job-price-cache-warmup

Implement changes

• Add the job test file
• Cover happy paths and edge cases
• Verify with npm run test:backend

Example commit message

test: add tests for price cache warmup job

Guidelines

• Assignment required before starting
• PR must include a closing reference to this issue
• Timeframe: 72 hours