Improve local dev setup with Composer and PHPUnit in Docker container

- Remove dependency on globally installed Composer
- Provide a way to install and run Composer and PHPUnit in the container created by wp-env
- Document local dev/test/build setup

Author: eliot-akira

.gitignore

@@ -13,8 +13,6 @@ node_modules
 # Ignore lock files to allow any package manager
 bun.lock
 bun.lockb
-composer.lock
-# package-lock.json
 yarn.lock
 
 # Testing

composer.json

@@ -1,23 +1,11 @@
 {
   "name": "tangible/fields",
-  "repositories": [
-    {
-      "type": "vcs",
-      "url": "git@github.com:tangibleinc/framework.git"
-    },
-    {
-      "type": "vcs",
-      "url": "git@github.com:tangibleinc/updater.git"
-    }
-  ],
+  "repositories": [],
   "require-dev": {
-    "phpunit/phpunit": "^9",
-    "yoast/phpunit-polyfills": "^1.0"
-  },
-  "require": {
-    "tangible/framework": "dev-main",
-    "tangible/updater": "dev-main"
+    "phpunit/phpunit": "^9.6",
+    "yoast/phpunit-polyfills": "^2.0"
   },
+  "require": {},
   "config": {
     "allow-plugins": {
       "roots/wordpress-core-installer": true