Migration 072 adds projects.sandbox_extensions (jsonb null): a per-service
extension/module map a venture declares up front (e.g. {"postgres":
["vector","postgis"],"redis":["search"]}). Additive + nullable so
existing opted-in projects stay byte-for-byte bare — no default set, opters
set the extensions they need explicitly (TimescaleDB out unless asked).
Project model validates the map against SANDBOX_ENGINE_FEATURES: unknown
service keys and unallowed features are rejected at the model boundary with
the allowlist named (plpython3u — superuser-RCE — excluded by construction),
empty feature lists drop to bare, order normalized + deduped. The allowlist
is the security containment, not privilege. Mirrors sandbox_services: not on
ProjectCreate, only Project + ProjectUpdate.
request_sandbox gains an extensions arg; _sandbox_features_scope unions a
per-call override with the project's standing set (trusted), bounds it to the
opted set + allowlist, rejects a non-opted service or unallowed feature with
the allowlist named in remediate — scope-first priority preserved by
rej_scope or rej_features. ensure_sandbox threads features through to
provision(); cache-by-features: a cached entry satisfies a new call iff
services are a subset AND every requested feature per service is already
cached — a feature superset re-provisions (rotates creds), mirroring the
services-superset case. available_extensions rides the evidence payload so an
agent doesn't guess what was activated.
Gate: ruff clean, mypy clean (9 modules), 51 tests pass (incl. migration
round-trip).
