refactor(root): move root artefacts to their canonical locations

.github/CONTRIBUTING.md

@@ -0,0 +1,88 @@
+<!--
+SPDX-License-Identifier: CC-BY-SA-4.0
+Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
+-->
+# Getting started
+```bash
+git clone https://github.com/hyperpolymath/heterogenous-mobile-computing.git
+cd heterogenous-mobile-computing
+
+# Using mise (recommended: provision the pinned toolchain)
+mise install
+
+# Task runner (see Justfile)
+just --list          # available tasks
+just check           # verify setup / static checks
+just test            # run the test suite
+```
+
+---
+
+## How to Contribute
+
+### Reporting Bugs
+
+**Before reporting**:
+1. Search existing issues
+2. Check if it's already fixed in `main`
+3. Determine which perimeter the bug affects
+
+**When reporting**:
+
+Use the [bug report template](.github/ISSUE_TEMPLATE/bug_report.md) and include:
+
+- Clear, descriptive title
+- Environment details (OS, versions, toolchain)
+- Steps to reproduce
+- Expected vs actual behaviour
+- Logs, screenshots, or minimal reproduction
+
+### Suggesting Features
+
+**Before suggesting**:
+1. Check the [roadmap](../docs/status/ROADMAP.adoc) if available
+2. Search existing issues and discussions
+3. Consider which perimeter the feature belongs to
+
+**When suggesting**:
+
+Use the [feature request template](.github/ISSUE_TEMPLATE/feature_request.md) and include:
+
+- Problem statement (what pain point does this solve?)
+- Proposed solution
+- Alternatives considered
+- Which perimeter this affects
+
+### Your First Contribution
+
+Look for issues labelled:
+
+- [`good first issue`](https://github.com/hyperpolymath/heterogenous-mobile-computing/labels/good%20first%20issue) — Simple Perimeter 3 tasks
+- [`help wanted`](https://github.com/hyperpolymath/heterogenous-mobile-computing/labels/help%20wanted) — Community help needed
+- [`documentation`](https://github.com/hyperpolymath/heterogenous-mobile-computing/labels/documentation) — Docs improvements
+- [`perimeter-3`](https://github.com/hyperpolymath/heterogenous-mobile-computing/labels/perimeter-3) — Community sandbox scope
+
+---
+
+## Development Workflow
+
+### Branch Naming
+```
+docs/short-description       # Documentation (P3)
+test/what-added              # Test additions (P3)
+feat/short-description       # New features (P2)
+fix/issue-number-description # Bug fixes (P2)
+refactor/what-changed        # Code improvements (P2)
+security/what-fixed          # Security fixes (P1-2)
+```
+
+### Commit Messages
+
+We follow [Conventional Commits](https://www.conventionalcommits.org/):
+```
+<type>(<scope>): <description>
+
+[optional body]
+
+[optional footer]
+```

.github/workflows/dogfood-gate.yml

@@ -41,7 +41,7 @@ jobs:
 
       - name: Validate A2ML manifests
         if: steps.detect.outputs.count > 0
-        run: bash .githooks/validate-a2ml.sh
+        run: bash .github/hooks/validate-a2ml.sh
       - name: Write summary
         run: |
           A2ML_COUNT="${{ steps.detect.outputs.count }}"
@@ -85,7 +85,7 @@ jobs:
 
       - name: Validate K9 contracts
         if: steps.detect.outputs.k9_count > 0
-        run: bash .githooks/validate-k9.sh
+        run: bash .github/hooks/validate-k9.sh
       - name: Write summary
         run: |
           K9_COUNT="${{ steps.detect.outputs.k9_count }}"

QUICKSTART-MAINTAINER.adoc

@@ -31,7 +31,7 @@ Output: `{{BUILD_OUTPUT_PATH}}`
 
 [source,bash]
 ----
-guix build -f guix.scm
+guix build -f build/guix.scm
 ----
 
 === Nix