Establish Railiance architecture home

SCOPE.md

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+# SCOPE
+
+> This file helps you quickly understand what this repository is about,
+> when it is relevant, and when it is not.
+> It is intentionally lightweight and may be incomplete.
+
+---
+
+## One-liner
+
+Architecture-definition home for Railiance: repository taxonomy, framework ADRs,
+cross-repo boundary rules, and cross-repo workplans for architecture changes.
+
+---
+
+## Core Idea
+
+`railiance-master` is the framework-level architecture repo for Railiance.
+It exists so shared concepts such as `railiance-*`, `rail-*`, `rapp-*`, and
+`reef-*` are defined once, with explicit boundaries, before they spread across
+implementation repos.
+
+It also serves as the natural workplan home for changes that span multiple
+Railiance repos and cannot be owned cleanly by only one of them.
+
+---
+
+## In Scope
+
+- Framework-level architecture documents for Railiance
+- Repository taxonomy and naming conventions
+- Architectural boundaries between ownership repos, rails, `rapp`s, and reefs
+- Architecture decision records affecting multiple Railiance repos
+- Cross-repo Railiance workplans whose implementation spans multiple sibling repos
+
+---
+
+## Out of Scope
+
+- OS provisioning and host hardening work owned by `railiance-infra`
+- Kubernetes runtime implementation owned by `railiance-cluster`
+- Platform-service implementation owned by `railiance-platform`
+- Application release implementation owned by `railiance-apps`
+- Forge runtime implementation owned by `railiance-forge`
+- Fabric graph implementation owned by `railiance-fabric`
+
+---
+
+## Relevant When
+
+- Defining a new Railiance repo family or framework term
+- Clarifying boundaries between existing Railiance repos
+- Planning migrations that touch multiple Railiance repos
+- Recording a framework-level architecture decision
+
+---
+
+## Not Relevant When
+
+- The work belongs entirely inside one implementation repo
+- The work is operational rather than architectural
+- The work is workload-specific rather than framework-wide
+
+---
+
+## Current State
+
+- Status: maintained / evolving
+- Implementation: architecture baseline documents are present and the first cross-repo separation workplan has been completed and handed off to sibling repos
+- Stability: evolving
+- Usage: internal Railiance framework architecture home and handoff point for cross-repo planning
+
+The repo now holds the canonical framework decisions and boundary documents for
+separating `rail-*`, `rapp-*`, and `reef-*` concerns out of the existing
+Railiance repos. Active implementation follow-up continues in the sibling
+ownership repos.
+
+---
+
+## How It Fits
+
+- Upstream dependencies: `the-custodian` canon and State Hub conventions
+- Downstream consumers: all `railiance-*`, future `rail-*`, future `rapp-*`, and future `reef-*` repos
+- Often used with: `railiance-fabric`, `railiance-platform`, `railiance-cluster`, `state-hub`
+
+---
+
+## Terminology
+
+- Preferred terms: architecture home, repository axis, rail, `rapp`, reef, ownership repo
+- Also known as: framework architecture repo
+- Potentially confusing terms: this repo defines framework structure; it does not implement the lower-layer systems it describes
+
+---
+
+## Related / Overlapping Repositories
+
+- `railiance-fabric` — models the ecosystem graph; `railiance-master` defines framework taxonomy and boundaries
+- `state-hub` — indexes and coordinates work; `railiance-master` provides the framework architecture to be coordinated
+- `repo-scoping` — explains what repos are useful for; `railiance-master` defines how Railiance repo families fit together
+
+---
+
+## Getting Oriented
+
+- Start with: `README.md`, `INTENT.md`
+- Key files / directories: `docs/`, `history/`, `workplans/`
+- Entry points: `docs/repository-axes.md`, `docs/reef-substrate-model.md`, `docs/adr/`
+
+---
+
+## Provided Capabilities
+
+```capability
+type: documentation
+title: Railiance repository taxonomy
+description: Defines the canonical Railiance repo families and how ownership repos, rails, managed workloads, and substrate boundaries compose.
+keywords: [railiance, architecture, taxonomy, rail, rapp, reef]
+```
+
+```capability
+type: governance
+title: Railiance framework architecture decisions
+description: Records framework-level architecture decisions and boundary guidance for changes spanning multiple Railiance repos.
+keywords: [architecture, adr, governance, boundaries, framework]
+```
+
+---
+
+## Notes
+
+Use this repo for architecture that must stay shared. Push concrete
+implementation outward into the ownership repos once the framework boundary is clear.