refactor(root): relocate the contributing guide into .github/

The estate canonical location is .github/CONTRIBUTING.md, which GitHub
auto-discovers; the root copy is removed and references are updated in the same
change.

Committed through the git index rather than a worktree: this repository carries
very large training-data blobs whose checkout exceeds the runner's writable
space, so the change is applied with `git apply --cached` and written with
`git write-tree`.

Author: hyperpolymath

.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/echidna.git
+cd echidna
+
+# 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/echidna/labels/good%20first%20issue) — Simple Perimeter 3 tasks
+- [`help wanted`](https://github.com/hyperpolymath/echidna/labels/help%20wanted) — Community help needed
+- [`documentation`](https://github.com/hyperpolymath/echidna/labels/documentation) — Docs improvements
+- [`perimeter-3`](https://github.com/hyperpolymath/echidna/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/canonical-references/prover-counts.yml

@@ -39,7 +39,7 @@ scope:
     - EXPLAINME.adoc
     - CLAUDE.md
     - CONTRIBUTING.md
-    - CONTRIBUTING.adoc
+    - ../../.github/CONTRIBUTING.md
     - QUICKSTART-USER.adoc
     - QUICKSTART-DEV.adoc
     - QUICKSTART-MAINTAINER.adoc

CLAUDE.md

@@ -19,7 +19,7 @@ Guidelines and context for working with Claude Code on the ECHIDNA project.
 - **Environment variables**: [`docs/ENV-VARS.md`](docs/ENV-VARS.md)
 - **RSR / CCCP compliance statement**: [`RSR_COMPLIANCE.adoc`](RSR_COMPLIANCE.adoc)
 - **Receipts for README claims**: [`EXPLAINME.adoc`](EXPLAINME.adoc)
-- **Contributor guide**: [`CONTRIBUTING.adoc`](CONTRIBUTING.adoc)
+- **Contributor guide**: [`.github/CONTRIBUTING.md`](.github/CONTRIBUTING.md)
 
 ## Repository Structure
 

CONTRIBUTING.adoc

@@ -8,7 +8,7 @@ ratified. GitHub renders AsciiDoc directly.
 Related:
 
 * link:MAINTAINERS.adoc[`+MAINTAINERS.adoc+`] — who maintains what
-* link:CONTRIBUTING.adoc[`+CONTRIBUTING.adoc+`] — contribution process
+* link:.github/CONTRIBUTING.md[`+.github/CONTRIBUTING.md+`] — contribution process
 * link:CODE_OF_CONDUCT.md[`+CODE_OF_CONDUCT.md+`] — expected conduct
 * link:RSR_COMPLIANCE.adoc[`+RSR_COMPLIANCE.adoc+`] — compliance
 statement

GOVERNANCE.adoc

@@ -147,7 +147,7 @@ CONTRIBUTIONS
 Contributions are licensed under the licence governing the part of the tree
 they land in: AGPL-3.0-or-later for application code, MPL-2.0 for the
 machine-readable specification surface and echidna-playground/, and
-CC-BY-SA-4.0 for documentation. See CONTRIBUTING.adoc.
+CC-BY-SA-4.0 for documentation. See .github/CONTRIBUTING.md.
 
 By contributing, you certify that:
   1. You have the right to submit the contribution.

NOTICE

@@ -92,9 +92,9 @@ just assail        # panic-attacker security scan (requires panic-attack CLI)
 ----
 
 All commits must be GPG-signed and follow Conventional Commits — see
-link:CONTRIBUTING.adoc[`CONTRIBUTING.adoc`] for the full policy.
+link:.github/CONTRIBUTING.md[`.github/CONTRIBUTING.md`] for the full policy.
 
 == Contributing
 
-See link:CONTRIBUTING.adoc[CONTRIBUTING.adoc] for guidelines (the
+See link:.github/CONTRIBUTING.md[.github/CONTRIBUTING.md] for guidelines (the
 canonical, AsciiDoc version). `CONTRIBUTING.md` is a thin pointer.

QUICKSTART-DEV.adoc

@@ -84,15 +84,15 @@ gh repo view hyperpolymath/echidna --json licenseInfo
 
 Seven files (later found to be 29) carried `+Palimpsest-0.6+` in their
 SPDX identifier. The owner ruled these were never a deliberate legal
-grant: `+CONTRIBUTING.adoc+` already recorded that the Palimpsest
+grant: `+../.github/CONTRIBUTING.md+` already recorded that the Palimpsest
 licence proper "`is the legal licence only on `+palimpsest-license+`,
 `+palimpsest-plasma+`, and (prospectively) `+consent-aware-http+``", and
 that in ECHIDNA it is an _ethical framework_ reference, orthogonal to
 the SPDX choice. Version 0.6 is also superseded by the
 `+hyperpolymath/palimpsest-license+` repository.
 
 All Palimpsest SPDX identifiers were therefore removed. The framework
-reference is preserved in `+CONTRIBUTING.adoc+` and `+NOTICE+`, which
+reference is preserved in `+../.github/CONTRIBUTING.md+` and `+NOTICE+`, which
 now state explicitly that it is not a grant, so this cannot drift back
 in silently.
 

docs/DEBT.adoc

@@ -382,7 +382,7 @@ deno task test:proofs
 
 == Contributing
 
-We welcome contributions! Please see link:CONTRIBUTING.adoc[CONTRIBUTING.adoc] for guidelines.
+We welcome contributions! Please see link:../.github/CONTRIBUTING.md[../.github/CONTRIBUTING.md] for guidelines.
 
 === Development Philosophy