runtimeHelpers imports infrastructure adapters and branches on plumbing presence

[flyingrobots]

Migrated from Method backlog

GitHub Issues are now the live work tracker. Repository docs remain Method evidence.

Field	Value
Source backlog	docs/method/backlog/bad-code/HEX_runtimehelpers-plumbing-composition-leak.md
Archived source	docs/archive/backlog/github-issue-migration-2026-06-01/docs/method/backlog/bad-code/HEX_runtimehelpers-plumbing-composition-leak.md
Original lane	bad-code
Original id	HEX_runtimehelpers-plumbing-composition-leak
Original legend	HEX
Original feature	materialization-query-index
Original release home	v17.0.0

Original backlog card

runtimeHelpers imports infrastructure adapters and branches on plumbing presence

Effort: M

What's Wrong

runtimeHelpers.ts auto-constructs CasBlobAdapter and
CborIndexStoreAdapter from domain-side helpers and uses
persistence.plumbing presence to choose the path. This is another
domain-to-infrastructure composition leak.

Why It Matters

The helper is effectively a hidden composition root inside
src/domain/**. That makes the domain depend on adapter details and
invites more .plumbing peeking over time.

Evidence

• src/domain/runtimeHelpers.ts:25
• src/domain/runtimeHelpers.ts:29
• src/domain/runtimeHelpers.ts:32
• src/domain/runtimeHelpers.ts:69

Suggested Fix

1. Remove infrastructure adapter imports from
   src/domain/runtimeHelpers.ts.
2. Push blob storage and index store construction into a composition
   root or explicit factory.
3. Replace plumbing-presence inference with explicit injected
   capabilities.