fix: refresh Netlify Blob client per request

[jackwalkerlabs]

Incident

ReleaseCue's static site remained available, but stateful API requests began returning HTTP 500 from a warm Netlify function.

Root cause

The function cached a Netlify Blob store/client in module scope. That client retained request-scoped credentials beyond their lifetime, so a warm function instance kept using expired credentials.

Fix

• construct the strongly consistent Blob store and API handler on every invocation
• add regression coverage preventing module-level API/client caching

Verification

• 6/6 tests pass
• production build passes
• JavaScript syntax checks pass
• production dependency audit reports 0 vulnerabilities
• independent review: APPROVE, no blocking findings
• Netlify draft deploy: homepage 200, metrics API 200 on 10 consecutive requests, anonymous private access 401
• direct authenticated Blob read confirmed persisted data remains intact

No data loss was detected.