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

src/jsonPointer.ts

@@ -1,4 +1,5 @@
 import { findNodeAtLocation, Node, parseTree } from 'jsonc-parser';
+import { isMap, isScalar, isSeq, parseDocument } from 'yaml';
 
 export interface OffsetRange {
   start: number;
@@ -37,3 +38,42 @@ export function rangeForPointer(text: string, pointer: string | undefined): Offs
   }
   return { start: node.offset, end: node.offset + node.length };
 }
+
+/** The same mapping for YAML text (`.archify` files). */
+export function rangeForPointerYaml(text: string, pointer: string | undefined): OffsetRange {
+  const doc = parseDocument(text, { keepSourceTokens: false, uniqueKeys: false });
+  let node: unknown = doc.contents;
+  let keyRange: [number, number] | undefined;
+  for (const segment of pointerSegments(pointer ?? '')) {
+    if (isMap(node)) {
+      const pair = node.items.find((item) => isScalar(item.key) && String(item.key.value) === String(segment));
+      if (!pair) break;
+      keyRange = isScalar(pair.key) && pair.key.range ? [pair.key.range[0], pair.key.range[1]] : undefined;
+      node = pair.value;
+    } else if (isSeq(node) && typeof segment === 'number' && segment < node.items.length) {
+      keyRange = undefined;
+      node = node.items[segment];
+    } else {
+      break;
+    }
+  }
+  if ((isMap(node) || isSeq(node)) && keyRange) return { start: keyRange[0], end: keyRange[1] };
+  const range = (node as { range?: [number, number, number] } | null)?.range;
+  if (!range) return { start: 0, end: 0 };
+  if (isMap(node) || isSeq(node)) return { start: range[0], end: Math.min(range[0] + 1, range[1]) };
+  return { start: range[0], end: range[1] };
+}
+
+export interface SyntaxProblem extends OffsetRange {
+  message: string;
+}
+
+/** YAML syntax errors with their offsets (none for valid YAML). */
+export function yamlSyntaxProblems(text: string): SyntaxProblem[] {
+  const doc = parseDocument(text, { uniqueKeys: false });
+  return doc.errors.map((error) => ({
+    start: error.pos[0],
+    end: Math.max(error.pos[1], error.pos[0] + 1),
+    message: error.message.split('\n')[0],
+  }));
+}