fix(api): disable response cache on miners, dashboard, and repos GET endpoints

[andriypolanski]

Summary

• Opt scoring-facing GET endpoints out of the global 60s response cache via @NoCache(), matching /pulls/.../files and /health.
• Affected routes: GET /api/v1/miners/:id/pulls, GET /api/v1/miners/:id/issues, GET /api/v1/dashboard/issues, GET /api/v1/repos/:owner/:repo/maintainers.
• Webhook ingestion updates the DB immediately, but previously these GET handlers could return stale cached payloads for up to one minute in production.

Fixes #201

Type of Change

• Bug fix
• New feature
• Refactor
• Documentation
• Other (describe below)

Testing

• npm run build in packages/das passes
• npm run lint passes
• npm run format:check passes
• Manual: with NODE_ENV=production and Redis configured, merge a PR and confirm repeated GET /api/v1/miners/{id}/pulls returns updated state/merged_at without waiting for cache TTL

Checklist

• I have read the Contributing Guide
• Code builds without errors
• New and existing tests pass (if applicable)
• Documentation updated (if applicable)
• No unnecessary dependencies added