feat: warm market data cache every 15 minutes

[Mustapha3415]

Summary

• Warm the top 20 configured Ethereum asset prices and default public yield opportunities.
• Cache market data for 15 minutes and refresh it every 15 minutes.
• Launch initial warming in the background so remote data sources do not delay application startup.
• Cache price feed and yield opportunity controller responses and add warmer coverage.

Closes #161

Validation

• git diff --check passed.
• Jest tests could not be run because this checkout has no installed node_modules dependencies.

[github-actions]

Code Review & Auto-Merge — @dorismaduegbunam 🚀

Thank you @Mustapha3415 for your contribution!

• PR Title: feat: warm market data cache every 15 minutes

• Author: @Mustapha3415

• Branch: fix/issue-161 -> main

• Status: Approved & Merged into main.

Verified code changes and repository requirements. Merging pull request.