architecture

docs/architecture/overview.md

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+# Architecture Overview
+
+This repository contains both the active legacy PHP game and an in-progress
+TypeScript rewrite. The legacy engine remains the source of truth while the
+monorepo plan is prepared alongside it.
+
+## Layers
+
+- Legacy runtime: PHP entry points under `legacy/` and `legacy/hwe/`
+- Legacy engine core: domain logic under `legacy/hwe/sammo/`
+- Legacy frontend: Vue/TypeScript under `legacy/hwe/ts/`
+- Rewrite (planned): pnpm workspace monorepo under `packages/` and `app/`
+
+## Data and State
+
+- PHP engine owns authoritative gameplay state today
+- Scenario and unit pack data are loaded from `legacy/hwe/scenario/`
+- Deterministic RNG is required for gameplay outcomes
+
+## Cross-Cutting Policies
+
+- No ad-hoc randomness for gameplay; use deterministic RNG
+- Keep domain logic independent of endpoints or UI
+- Prefer clear Korean comments in core gameplay logic for maintainers
+
+## Runtime Processing (Outline)
+
+This document links to detailed runtime behavior in `docs/architecture/runtime.md`.
+Use that document for turn daemon scheduling, API request handling, and
+persistence sequencing.