0.3.0: .archify files are YAML and open straight into the diagram

- .archify content is YAML (JSON still accepted); converted to JSON for the renderer
- Archify Diagram custom editor is the default for *.archify; Show Source opens the YAML beside it
- YAML syntax errors and validation problems mapped to YAML lines
- yamlValidation for schema completion with redhat.vscode-yaml
- scripts/to-yaml.mjs converts existing .archify files

test/schema.test.ts

@@ -3,6 +3,7 @@ import fs from 'node:fs';
 import path from 'node:path';
 import { test } from 'node:test';
 import Ajv2020 from 'ajv/dist/2020';
+import { parse as parseYaml } from 'yaml';
 
 const root = path.resolve(__dirname, '..', '..');
 const schemas = path.join(root, 'schemas');
@@ -27,14 +28,14 @@ test('bundled schemas carry no absolute $id', () => {
 test('the .archify schema accepts every fixture', () => {
   const validate = validator();
   for (const file of fs.readdirSync(fixtures)) {
-    const ok = validate(JSON.parse(fs.readFileSync(path.join(fixtures, file), 'utf8')));
+    const ok = validate(parseYaml(fs.readFileSync(path.join(fixtures, file), 'utf8')));
     assert.ok(ok, `${file}: ${JSON.stringify(validate.errors?.slice(0, 3))}`);
   }
 });
 
 test('the .archify schema applies the schema of the declared type', () => {
   const validate = validator();
-  const sequence = JSON.parse(fs.readFileSync(path.join(fixtures, 'cache-miss.archify'), 'utf8'));
+  const sequence = parseYaml(fs.readFileSync(path.join(fixtures, 'cache-miss.archify'), 'utf8'));
   // A sequence diagram is not a valid architecture diagram.
   assert.equal(validate({ ...sequence, diagram_type: 'architecture' }), false);
   assert.equal(validate({ ...sequence, diagram_type: 'poster' }), false);