refactor: make ARNES external-repo based with ticket publish flow

docs/repository-layout.md

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+# Repository layout
+
+## Core idea
+- ARNES core lives at repository root once installed into a project repo.
+- The source repo of ARNES is not the repo where product work should happen.
+- Real project code lives in `project/` by default.
+- Project-specific rules live in overlays, not in core files.
+
+## Main directories
+- `project/` — real app code
+- `backlog/` — ticket list and feature state
+- `work/` — runtime state, history, artifacts
+- `harness/` — workflow, roles, policies, contracts
+- `spec/` — product, tech, acceptance, SDD, BDD source docs
+- `features/` — optional executable BDD runner assets
+- `scripts/` — start, verify, ticket creation, runtime status
+- `platforms/` — platform adapters (pi, opencode)
+- `defaults/` — optional starter assets
+
+## Recommended separation
+- Core ARNES should stay generic.
+- Domain checks go in `scripts/verify.local.sh`.
+- Domain rules go in `AGENTS.local.md`.
+- Real code should not be mixed into `harness/`, `work/`, `backlog/`, or `spec/`.
+
+## Default project shape
+```text
+project/
+├── README.md
+├── templates/
+├── static/
+│   ├── css/
+│   ├── js/
+│   └── images/
+└── ...
+```
+
+This shape is only a default. The wizard can target another app directory if needed.