chore: establish M0 project foundations

Document accepted MVP decisions, add AGPL-3.0-only licensing, scaffold repository boundaries, and configure verified PSR-12 and foundation checks.

Refs #1, #2, #3, #4, #5

composer.json

@@ -0,0 +1,20 @@
+{
+    "name": "keith/meshvault",
+    "description": "Self-hosted 3D model library",
+    "type": "project",
+    "license": "AGPL-3.0-only",
+    "require": {
+        "php": ">=8.3"
+    },
+    "require-dev": {
+        "squizlabs/php_codesniffer": "^3.13.5"
+    },
+    "scripts": {
+        "lint": "phpcs --standard=phpcs.xml.dist",
+        "test": "@php tests/foundation.php"
+    },
+    "config": {
+        "sort-packages": true,
+        "allow-plugins": false
+    }
+}