## Lesson — Provide a dummy fallback API key (e.g., 'local-only')

**Tags:** architecture, curated
**Pattern:** \bapiKey:\s*process\.env\.[A-Z0-9_]+(?!\s*(\|\||\?\?))
**Engine:** regex
**Scope:** **/*.ts, **/*.tsx, **/*.js, **/*.jsx, !**/*.test.ts
**Severity:** error

Provide a dummy fallback API key (e.g., 'local-only').
