`[2026-06-19]` **#18 D1 SHIPPED — composite `build_combined_app` on `:8392` (`v0.17.16`, `7f4ceaa`); #18 CLOSED; published `v0.18.0` (`359dbb1`).** `build_combined_provider_app` wraps bifrost's public builder over both stores + the shared read route; op-feed `plane='combined'` per-path. Direct in-session TDD; heid-code-review panel (Gróa/Hulda/Regin) returned ZERO drift. Live-proven at wire+dispatch; WT-turn gated on infra-ops `:8392` allowlist.