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.

  * .github/CONTRIBUTING.md
      (new)
  * CONTRIBUTING.adoc
      (deleted)
  * docs/NAVIGATION.adoc
  * docs/README.adoc
  * docs/ROADMAP.adoc

Author: hyperpolymath

.github/CONTRIBUTING.md

@@ -0,0 +1,181 @@
+# Contributing to AffineScript
+
+Thank you for your interest in AffineScript — a practical language for
+resource-safe systems, compiling to typed WebAssembly. This guide covers
+how to set up a working tree, file useful bugs, and submit changes.
+
+For the language itself, start from [`README.adoc`](README.adoc). For
+project state, blockers, and next-actions, see
+[`.machine_readable/descriptiles/STATE.a2ml`](.machine_readable/descriptiles/STATE.a2ml).
+
+’’’’’
+
+## Quick Start
+
+``` bash
+git clone https://github.com/hyperpolymath/affinescript.git
+cd affinescript
+
+# Provision the OCaml toolchain (one-shot). See README.adoc "Getting Started"
+# for the full list of opam packages and the `eval $(opam env)` note for
+# non-interactive shells.
+opam install -y \
+  sedlex menhir ppx_deriving ppx_sexp_conv sexplib0 fmt cmdliner yojson \
+  alcotest ocamlformat \
+  js_of_ocaml js_of_ocaml-ppx js_of_ocaml-compiler
+eval "$(opam env --switch=default --set-switch)"
+
+# Verify setup
+dune build
+dune runtest
+```
+
+Tested on OCaml 4.14.2 (the constraint in `dune-project` is `>=`
+`4.14`).
+
+### Repository Structure
+
+    affinescript/
+    ├── lib/                 # Compiler core (lexer, parser, typechecker, codegen, verifier)
+    ├── bin/                 # CLI driver — `_build/default/bin/main.exe`
+    ├── stdlib/              # Standard library `.affine` modules
+    ├── test/                # Alcotest suites (lexer, golden, e2e fixtures)
+    ├── tests/               # Topic-grouped tests (borrow, codegen, effects, parser, …)
+    ├── examples/            # Self-contained example programs
+    ├── conformance/         # Conformance test corpus
+    ├── docs/                # Specs, decisions, guides
+    ├── packages/            # Aggregate JS/TS/ binding packages
+    ├── editors/             # Editor integrations
+    ├── js/                  # `js_of_ocaml` playground (built into `playground.bc.js`)
+    ├── .machine_readable/   # Machine-readable metadata (`.a2ml`) — see 0-AI-MANIFEST.a2ml
+    ├── .github/             # CI workflows, issue templates
+    ├── CODE_OF_CONDUCT.md
+    ├── CONTRIBUTING.md      # This file
+    ├── LICENSE / LICENSES   # MIT OR AGPL-3.0-or-later
+    ├── MAINTAINERS.adoc
+    ├── README.adoc
+    ├── SECURITY.md
+    ├── dune-project
+    └── justfile
+
+’’’’’
+
+## How to Contribute
+
+### Reporting Bugs
+
+**Before reporting:** 1. Search [existing
+issues](https://github.com/hyperpolymath/affinescript/issues). 2. Check
+that the bug reproduces against `main` (`git` `pull` `&&` `dune`
+`build`).
+
+**When reporting:** use the [bug report
+template](.github/ISSUE_TEMPLATE/bug_report.md) and include:
+
+- Clear, descriptive title.
+
+- Environment: OCaml version, opam switch, OS.
+
+- Steps to reproduce, ideally as a minimal `.affine` file plus the exact
+  `dune` `exec` `affinescript` `--` `<subcommand>` `<file>` invocation.
+
+- Expected vs actual behaviour (compiler output, generated Wasm, runtime
+  trap, etc.).
+
+### Suggesting Features
+
+**Before suggesting:** 1. Skim [`docs/ROADMAP.adoc`](docs/ROADMAP.adoc)
+and `.machine_readable/descriptiles/STATE.a2ml`. 2. Search existing
+issues and discussions.
+
+**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 and any alternatives considered.
+
+- Whether the change touches the core language, a face (frontend
+  surface), a backend, or the stdlib.
+
+### Your First Contribution
+
+Look for issues labelled:
+
+- [`good` `first`
+  `issue`](https://github.com/hyperpolymath/affinescript/labels/good%20first%20issue)
+
+- [`help`
+  `wanted`](https://github.com/hyperpolymath/affinescript/labels/help%20wanted)
+
+- [`documentation`](https://github.com/hyperpolymath/affinescript/labels/documentation)
+
+’’’’’
+
+## Development Workflow
+
+### Branch Naming
+
+    docs/short-description       # Documentation
+    test/what-added              # Test additions
+    feat/short-description       # New features
+    fix/issue-number-description # Bug fixes
+    refactor/what-changed        # Code improvements
+    security/what-fixed          # Security fixes
+    ci/what-changed              # CI / tooling
+
+Branch from `main` and target `main` in your PR.
+
+### Commit Messages
+
+We follow [Conventional Commits](https://www.conventionalcommits.org/):
+
+    <type>(<scope>): <description>
+
+    [optional body]
+
+    [optional footer, e.g. closes #N or Co-Authored-By: ...]
+
+Common types: `feat`, `fix`, `docs`, `test`, `refactor`, `chore`, `ci`.
+Common scopes: `lexer`, `parser`, `typecheck`, `codegen`, `verify`,
+`stdlib`, `cli`, `readme`.
+
+### Required Checks
+
+Before opening a PR, locally:
+
+``` bash
+dune build       # must exit 0
+dune runtest     # must be green
+dune fmt         # optional — auto-formats with ocamlformat
+```
+
+The `methodology.a2ml` file lists the canonical gate set. CI will rerun
+`build` + `runtest` plus the security, lint, and policy workflows in
+`.github/workflows/`.
+
+### Pull Requests
+
+1.  Push your branch and open a PR against `main`.
+
+2.  Use a Conventional-Commit-shaped title.
+
+3.  In the body, summarise the change and link the issue it closes.
+
+4.  Keep PRs focused — split unrelated changes into separate PRs.
+
+5.  CI must be green. Maintainers squash-merge by default; commit
+    message lineage is preserved in the PR body.
+
+’’’’’
+
+## Code of Conduct
+
+This project follows the [Code of Conduct](CODE_OF_CONDUCT.md). By
+participating you agree to abide by it.
+
+## License
+
+By contributing you agree your contribution is licensed under the
+project’s dual licence (MIT OR AGPL-3.0-or-later), as recorded in
+[`LICENSE`](LICENSE) and per-file SPDX headers.

CONTRIBUTING.adoc

@@ -8,7 +8,7 @@ This guide helps you navigate the AffineScript repository structure.
 == Start here — by audience
 
 * *New users* — link:tutorial/lesson-01-hello.adoc[tutorial (lessons 1–10)], link:guides/warmup/[runnable warm-ups], link:../wiki/language-reference/[language reference].
-* *Developers / contributors* — this guide, link:../wiki/compiler/architecture.md[compiler architecture], link:decisions/[ADRs], link:governance/CONTRIBUTING.adoc[contributing].
+* *Developers / contributors* — this guide, link:../wiki/compiler/architecture.md[compiler architecture], link:decisions/[ADRs], link:governance/../.github/CONTRIBUTING.md[contributing].
 * *Maintainers* — link:governance/MAINTAINERS.adoc[maintainers], link:standards/RELEASE.adoc[release process], link:../.machine_readable/descriptiles/PLAYBOOK.a2ml[ops playbook], link:SOUNDNESS.adoc[soundness ledger].
 
 == Quick Start Files (Root Level)
@@ -57,7 +57,7 @@ This guide helps you navigate the AffineScript repository structure.
 
 **Governance documents:**
 
-* link:governance/CONTRIBUTING.adoc[Contributing Guide] - How to contribute
+* link:governance/../.github/CONTRIBUTING.md[Contributing Guide] - How to contribute
 * link:governance/CODE_OF_CONDUCT.md[Code of Conduct] - Community standards
 * link:governance/SECURITY.md[Security Policy] - Reporting vulnerabilities
 * link:governance/MAINTAINERS.adoc[Maintainers] - Project maintainers
@@ -156,7 +156,7 @@ just fmt             # Format code
 
 === Contributing
 
-1. Read link:governance/CONTRIBUTING.adoc[Contributing Guide]
+1. Read link:governance/../.github/CONTRIBUTING.md[Contributing Guide]
 2. Check link:governance/CODE_OF_CONDUCT.md[Code of Conduct]
 3. Review link:standards/DECISIONS.adoc[Architecture Decisions]
 4. Follow link:standards/ROADMAP.adoc[Development Roadmap]