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/health read the APP_VERSION environment variable directly, but docker-compose passes App__Version, which binds to the App:Version configuration key. The variable under that name never existed in the container, so the endpoint always reported "unknown". Read App:Version through IConfiguration, the approach AdminSystemController already used for the same value. The resolution rule (configured version, else assembly version) moves to a shared BuildMetadata helper rather than being written twice; AdminSystemController now calls it, so the admin page and /health cannot drift apart. Local development is unaffected: nothing sets App:Version there, and the assembly-version fallback still applies. Tests pin the configuration KEY, not just the behaviour, including that an App__Version environment variable binds to App:Version. The original bug failed silently, so a behavioural test alone would not have caught it. Verified against a running backend: App__Version=9.9.9-test reports 9.9.9-test; unset reports the assembly version rather than "unknown". Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>