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

.github/CONTRIBUTING.md

@@ -0,0 +1,35 @@
+# Contributing to ephapax
+
+This document explains how to contribute to the project. We follow a
+"Dual-Track" architecture where human-readable documentation lives in
+the root and machine-readable policies live in `.machine_readable/`.
+
+## How to Contribute
+
+We welcome contributions in many forms: \* **Code:** Improving the core
+verified stack or extensions. \* **Documentation:** Enhancing AsciiDoc
+manuals or AI manifests. \* **Testing:** Adding property-based tests or
+formal proofs.
+
+## Getting Started
+
+1.  **Read the AI Manifest:** Start with `0-AI-MANIFEST.a2ml` to
+    understand the repository structure.
+
+2.  **Environment:** Use `guix` `develop` or `direnv` `allow` to set up
+    your tools (Idris2, Zig, Rust).
+
+3.  **Task Runner:** Use `just` to see available commands (`just`
+    `--list`).
+
+## Contribution Policies
+
+For detailed rules on branch naming, commit messages, and the PR
+process, please refer to the machine-readable metadata in
+<a href=".machine_readable/"
+class="machine_readable/">.machine_readable/</a>.
+
+## Code of Conduct
+
+All contributors are expected to adhere to our ethical standards. See
+<a href="CODE_OF_CONDUCT.md" class="md">CODE_OF_CONDUCT</a> for details.

.machine_readable/root-allow.txt

@@ -1,2 +1,3 @@
 .hypatia-ignore
 CLAUDE.md
+build/                     # build orchestration: guix.scm relocated here (canon 1.2.1 guix-primary template_ref = "build/")

MAINTAINERS.adoc

@@ -62,4 +62,4 @@ For questions about project governance:
 
 * link:GOVERNANCE.adoc[Governance Model]
 * link:CODE_OF_CONDUCT.md[Code of Conduct]
-* link:CONTRIBUTING.adoc[Contributing Guide]
+* link:.github/CONTRIBUTING.md[Contributing Guide]

README.adoc

@@ -707,7 +707,7 @@ generics, effects, traits, comptime, contracts) lives on
 | link:spec/[spec/]
 | Language specification + grammar EBNF.
 
-| link:CONTRIBUTING.adoc[CONTRIBUTING.adoc]
+| link:.github/CONTRIBUTING.md[.github/CONTRIBUTING.md]
 | Contribution guide.
 
 | link:CODE_OF_CONDUCT.md[CODE_OF_CONDUCT.md]
@@ -764,7 +764,7 @@ comparison against ten of these.
 
 Contributions welcome. Please see:
 
-* link:CONTRIBUTING.adoc[CONTRIBUTING.adoc] — getting started
+* link:.github/CONTRIBUTING.md[.github/CONTRIBUTING.md] — getting started
 * link:CODE_OF_CONDUCT.md[CODE_OF_CONDUCT.md] — community standards
 
 The highest-leverage open work, in priority order:

docs/accessibility/README.adoc

@@ -244,7 +244,7 @@ Burble is committed to:
 * Supporting screen readers and other assistive technologies
 * Continuous improvement based on user feedback
 
-We welcome contributions to improve accessibility. See our link:../CONTRIBUTING.adoc[Contributing Guide] for details.
+We welcome contributions to improve accessibility. See our link:../../.github/CONTRIBUTING.md[Contributing Guide] for details.
 
 == Related Documents
 

docs/testing-and-bench-strategy.adoc

@@ -218,7 +218,7 @@ This layer keeps the four-layer-proof / dyadic-grammar / typed-wasm-seam machine
 
 *P2P.* contractile source → `contractile.just` byte-equality (catches generator/source drift); status-gate ↔ live `cargo test --list` + Coq admit grep ↔ `TEST-NEEDS.md`/`PROOF-NEEDS.md`; `pixi` tasks ↔ Justfile recipes (flag the lint asymmetry: pixi runs `clippy -D warnings`, Justfile has none); `reuse lint` ↔ LICENSES/ tree (would FAIL today: PMPL referenced but no `LICENSES/PMPL-*.txt`).
 
-*E2E.* Clean-room repro (`pixi run build && pixi run test`; `guix shell -f guix.scm -- cargo build` — flag that `guix.scm` has `(source #f)` so it only provisions a shell, *not a reproducible build*); doc-truth `just status-gate` (exit 0 with counts matching docs; mutate a stray `Admitted` → red); governance PR E2E (drop SPDX header / add unpinned action / bump version without CHANGELOG → each gate fires); `validate-wasm` corpus floor.
+*E2E.* Clean-room repro (`pixi run build && pixi run test`; `guix shell -f build/guix.scm -- cargo build` — flag that `guix.scm` has `(source #f)` so it only provisions a shell, *not a reproducible build*); doc-truth `just status-gate` (exit 0 with counts matching docs; mutate a stray `Admitted` → red); governance PR E2E (drop SPDX header / add unpinned action / bump version without CHANGELOG → each gate fires); `validate-wasm` corpus floor.
 
 *endpoint.* `reuse lint` exit code (SBOM-consumable attestation); scorecard MIN_SCORE=5 (*but the SARIF score-parse currently defaults to 0 via a `// 0` fallback — a false sense of coverage the test must expose*); status-gate markers exactly-one occurrence; Containerfile pinning contract; `boj-build` trigger payload (currently *malformed JSON*, unbalanced quotes/braces, `continue-on-error: true` swallows failures).