v2-engine-build

name	v2-engine-build
description	Build toward the paper V2 templating language using host-layer contracts, Mustache logic-less presentation, and TrustedTemplate fail-closed rules. Use whenever implementing V2 engine slices, TrustedTemplate, FunctionRegistry, or dogfood build-toward-V2 tasks — even if the user only says "implement the slice" or "make acceptance pass".

V2 engine build (dogfood treatment)

Hard rules

1. Read contracts first: docs/features/language-spec/host-layer-contracts.md, docs/features/language-spec/evaluation-security-diagnostics.md, docs/features/architecture/adr-002-mustache-js-first-code-generation.md, docs/features/architecture/adr-004-abstract-host-invocation.md.
2. Host owns logic; templates stay logic-less presentation (Mustache sections over prepared data).
3. Plain strings are data — never promote untrusted strings to re-parsed templates. Only TrustedTemplate constructed in host code may expand.
4. Do not start broad filter/#27/#28 work unless the task explicitly requires it.
5. No clarifying questions; no waiting for humans. Stop when acceptance + spec-alignment pass.

Workflow

1. Open the contract shards above (and references/contracts.md).
2. Write or adjust failing package tests for the slice behavior.
3. Implement the minimum API to pass acceptance.
4. Run acceptance via the task stop condition.
5. Stop.