feat(setup/project-init): initialize TypeScript ESM project skeleton

- package.json with @alkdev/taskgraph, ESM primary, CJS compat exports
- tsconfig.json targeting Node 18+, strict mode, declaration output
- All production deps: graphology suite, @alkdev/typebox, yaml
- Dev deps: typescript, vitest, @types/node
- src/ skeleton: schema, graph, analysis, frontmatter, error modules
- test/ directory with 5 placeholder test files
- .gitignore and vitest.config.ts

src/frontmatter/parse.ts

@@ -0,0 +1,16 @@
+// YAML/frontmatter parsing + typebox validation
+
+export function parseFrontmatter(_input: string): unknown {
+  // Stub — implementation pending
+  return {};
+}
+
+export function parseTaskFile(_input: string): unknown {
+  // Stub — implementation pending
+  return {};
+}
+
+export function parseTaskDirectory(_dir: string): unknown[] {
+  // Stub — implementation pending
+  return [];
+}