docs: add TOPOLOGY.md

Author: hyperpolymath

TOPOLOGY.md

@@ -0,0 +1,29 @@
+<!-- SPDX-License-Identifier: MPL-2.0 -->
+<!-- (PMPL-1.0-or-later preferred; MPL-2.0 required for VS Code marketplace) -->
+<!-- Copyright (c) 2026 Jonathan D.A. Jewell (hyperpolymath) <j.d.a.jewell@open.ac.uk> -->
+# TOPOLOGY.md — vscode-a2ml
+
+## Purpose
+
+VS Code extension providing syntax highlighting, language configuration, and snippets for A2ML (AI-to-Machine Language) files. Enables editor support for `.a2ml` manifests used across RSR repos. Published to the VS Code marketplace (MPL-2.0 required by platform).
+
+## Module Map
+
+```
+vscode-a2ml/
+├── syntaxes/                    # TextMate grammar for A2ML syntax highlighting
+├── snippets/                    # Code snippets for common A2ML patterns
+├── src/                         # Extension TypeScript entry point (marketplace req)
+├── icons/                       # File type icons
+├── language-configuration.json  # Bracket matching, comment config
+├── package.json                 # VS Code extension manifest
+└── docs/                        # Extension documentation
+```
+
+## Data Flow
+
+```
+[.a2ml file opened] ──► [syntaxes/ grammar] ──► [syntax highlighting]
+                   └──► [snippets/]          ──► [completions]
+                   └──► [language-config]    ──► [bracket/comment behaviour]
+```