CAP-122 — API versioning & request routing

Category	Platform & infrastructure
Business goal	Not yet linked to a business goal
Satisfying module	MOD-075
Mode	AUTO
BD owner	BD09 Technology
Human needed	No

Routes each API request to the correct service version based on the API-Version header or URL path, supporting multiple live versions simultaneously during migration windows. Deprecation notices are injected as response headers with sunset dates so consumers can track timelines without consulting documentation. Canary routing sends a configurable percentage of traffic to a new version for safe production validation.