feat(sandbox): pluggable per-engine registry (postgres/redis/mongo) (#324)

* feat(sandbox): pluggable per-engine registry (postgres/redis/mongo)

Replaces the hardcoded postgres+redis branches in the provisioner and the
env emitter with a registry of SandboxEngine specs (image, run args,
readiness probe, connection, ROBOCO_TEST_* env) in a pure low module
(roboco/models/sandbox.py). VALID_SANDBOX_SERVICES is derived from the
registry — single source of truth — and the provisioner + orchestrator
iterate it, so adding an engine is one class + one registry line, not
another branch. Adds a mongo:8-alpine engine (ROBOCO_TEST_MONGO_*) as the
third service alongside postgres/redis.

Also fixes the cold-pull loop that stranded v0.19.0 board agents with
empty error strings: docker run pulled inline under a 20s deadline, so a
NAS cold pull was killed, cancelled, and re-pulled from scratch forever.
_ensure_image now inspects + pulls (300s) before run; provisioning errors
log type+message so a bare TimeoutError no longer shows as "".

Panel edit-project dialog: postgres/redis toggles -> a Set<string>
multi-select driven by a SANDBOX_SERVICES catalog, so new engines appear
in the UI by adding to the catalog.

Tests: engine parity (allowlist==registry, unique slugs/images, no None
leak in env, SandboxInfo aggregates every engine), mongo provision + env
injection, plus the existing postgres/redis provision/env/spawn/janitor
suite updated to the registry shape. 821 unit / 5 skip green; ruff + mypy
(360 files) clean.

* docs(sandbox): reflect pluggable engine registry + mongo across docs

CHANGELOG (0.19.0): Added entry for the pluggable sandbox engine registry
(postgres/redis/mongo) + Fixed entry for the cold-pull loop/empty-error
strand that boarded v0.19.0 board agents.

docs/map (9 files): sandbox subsystem blurbs, SandboxProvisioner rows,
_maybe_provision_sandbox/_append_sandbox_env rows, feature-flag rows, the
migration-057 row + v0.17.0 delta, and the models.md VALID_SANDBOX_SERVICES
note — all retitled to DB/Redis/Mongo via the engine registry
(roboco/models/sandbox.py), with the one-class-one-line extension story and
the _ensure_image cold-pull fix. Production-network (roboco_data) lines left
as postgres+redis — mongo is sandbox-only, not a prod service.

docs/rag (3 files): sandbox-db.md rewritten around the registry (engine list,
generic _provision_engine, image pre-pull, ROBOCO_TEST_DB_*/REDIS_*/MONGO_*
incl. MONGO_AUTH_DB=admin, single emit_env); config-reference sandbox flag
row + subsection retitled; db-network-isolation framing broadened to
postgres/redis/mongo. preconditions-and-rejections left untouched (its hit
was an unrelated gateway see-also link).

* test(e2e): harden umbrella close terminal reads with bounded wait-for-state

The MegaTask umbrella close test flaked once on CI (ceo-approve returned
200 but the re-fetch saw awaiting_pm_review) then passed on re-run. The
production path is deterministic: complete -> main_pm_complete ->
submit_pm_review -> escalate_to_ceo -> ceo_approve -> commit, all on one
session, all awaited; the fire-and-forget completion hooks are isolated
(own session, best-effort, never touch task.status or the request session).
20 local runs could not reproduce it.

The one real surface is the read pattern: the e2e stack commits on the
uvicorn thread's loop and reads via a separate loop (run_db -> asyncio.run
with a fresh engine), so a terminal single point-read can race a
still-draining completion hook on a contended runner. Replace the two
terminal point-reads with a bounded wait_for_status poll. Strictly better
than a one-shot read: absorbs the transient, and a genuine state bug still
surfaces via the timeout branch asserting against the last-read state.

---------

Co-authored-by: Renn F <rennf93@users.noreply.github.com>

docs/map/deployment-tooling.md

@@ -251,7 +251,7 @@ deployment-tooling
 - ROBOCO_DEP_UPDATE_ENABLED / _INTERVAL_SECONDS / _MAX_OPEN_TASKS / _MAX_PER_CYCLE
 - ROBOCO_RELEASE_MANAGER_ENABLED / _MIN_COMMITS / _INTERVAL_SECONDS / _CI_WORKFLOW
 - ROBOCO_ORG_MEMORY_ENABLED / _TOP_K / _MIN_SCORE
-- ROBOCO_SANDBOX_DB_ENABLED — sandboxed per-agent-spawn Postgres/Redis provisioner (`roboco/runtime/sandbox.py`); a project also needs its `sandbox_services` column set
+- ROBOCO_SANDBOX_DB_ENABLED — sandboxed per-agent-spawn engine provisioner (`roboco/runtime/sandbox.py` + registry in `roboco/models/sandbox.py`); a project also needs its `sandbox_services` column set
 - ROBOCO_DB_NETWORK_ISOLATED — set true only by the compose topology carrying the `roboco_data` data-only network; suppresses the legacy prod-creds gate-env injection
 - ROBOCO_CLOUD_AUTH_ENABLED / _EMAIL / _PASSWORD / _SECRET / _COOKIE_MAX_AGE — FastAPI Users cookie login for the single seeded CEO; `Settings` fails loud at startup if armed with no secret
 - ROBOCO_X_ENGINE_ENABLED / _MENTIONS_INTERVAL_SECONDS / _MENTIONS_MAX_PER_CYCLE / _MENTIONS_MIN_ENGAGEMENT / _MAX_OPEN_POSTS / ROBOCO_X_ACCOUNT_USER_ID / _REQUEST_TIMEOUT_SECONDS — the X (Twitter) engine; inert without stored OAuth 1.0a credentials regardless of the flag