Auth: surface DB outage as 503 instead of 403

[CryptoJones]

Summary

attachAuth swallows DB errors from isMaster / getCompanyId into isMaster=false / companyId=-1, which downstream handlers treat as auth failure (403). Operators may misread a Postgres outage as invalid API keys.

Proposed fix

Surface infrastructure failures as 503 when auth lookups fail due to DB errors (called out as possible future fix in auth.js comments).

Acceptance criteria

• DB connectivity failure returns 503 on protected routes
• Invalid/missing keys still return 403
• Tests for both paths

Source

Code review backlog (2026-06-23)