docs: add TOPOLOGY.md

Author: hyperpolymath

TOPOLOGY.md

@@ -0,0 +1,31 @@
+<!-- SPDX-License-Identifier: PMPL-1.0-or-later -->
+<!-- Copyright (c) 2026 Jonathan D.A. Jewell (hyperpolymath) <j.d.a.jewell@open.ac.uk> -->
+# TOPOLOGY.md — a2ml-rs
+
+## Purpose
+
+Rust parser and renderer for A2ML (Attested Markup Language), a structured markup format with built-in attestation provenance, directive metadata, and trust-level tracking. Provides a complete parse-render round-trip with typed AST. Intended for use in CI tooling, validators, and server-side pipelines.
+
+## Module Map
+
+```
+a2ml-rs/
+├── src/
+│   ├── lib.rs         # Public crate API
+│   ├── types.rs       # AST types (blocks, inlines, directives, attestations)
+│   ├── parser.rs      # A2ML document parser
+│   ├── renderer.rs    # AST-to-A2ML surface syntax renderer
+│   └── error.rs       # Error types
+├── benches/           # Criterion benchmarks
+├── examples/          # Usage examples
+├── Cargo.toml
+└── container/         # Containerfile for CI
+```
+
+## Data Flow
+
+```
+[A2ML text] ──► [parser.rs] ──► [Typed AST] ──► [renderer.rs] ──► [A2ML text]
+                                     │
+                              [types.rs / error.rs]
+```