Add hq modeling runtime package scaffold

[roccho-dev]

Purpose

Create the ops-owned package boundary for the runtime side of editor-to-queue-to-ui.

Scope

• Add packages/hq-modeling-runtime/ scaffold.
• Add README explaining package ownership.
• Register the package in the ops build/check surface.
• Keep it empty/minimal until queue schema and worker issues add behavior.

Done

• hq-modeling-runtime exists as the canonical ops package for queue runtime.
• It is build/check visible.
• Docs point to Document ops as queue runtime and admission boundary #38 as the boundary issue.

Scope-achievement declaration

This issue is complete only when all of the following are true:

• Purpose lineage: creates the package home needed for editor-to-queue-to-ui without placing runtime in edits or ui.
• Core/port/adapter: scaffold defines directories or docs for core, ports, and adapters before behavior is added.
• Pure/effect split: scaffold states that core must be pure and side effects must live only in adapters.
• False-positive exclusion: checks must allow empty/minimal scaffold as long as boundaries are explicit.
• False-negative exclusion: checks must fail if scaffold places runtime side effects in core or mixes editor/UI code into runtime package.
• Authority boundary: scaffold must not create accepted state; it only prepares runtime ownership.
• Repo cleanliness: package layout must make later code placement obvious and prevent root-level sprawl.

Non-goals

• Do not implement queue validation here.
• Do not implement worker/admission/projection here.
• Do not change edits or ui.

Checks

• Package registration check passes.
• Layout/boundary check passes.
• Existing ops checks pass.

Depends on

• Document ops as queue runtime and admission boundary #38

Why this matters

This gives all queue-after-confirm work one ops-owned home before moving behavior into it.