refactor: named exports (run + descriptor), remove build pipeline

- Bundle contract: export const run + export const descriptor (no default export)
- add only accepts .esm.js, extracts descriptor via dynamic import → .yaml
- Removed: build-pipeline, generate-types, json-schema-to-ts
- Worker loads mod.run instead of mod.default
- Biome: no more noDefaultExport overrides for bundles
- 62 tests pass, biome clean

Closes #8
小橘 <xiaoju@shazhou.work>

packages/cli-workflow/__tests__/bundle-fixture.ts

@@ -1,9 +1,5 @@
-import type { ParsedAddArgv } from "../src/add-argv.js";
-
-export const MINIMAL_DESCRIPTOR_YAML = `description: "fixture"
-roles: {}
-`;
+import type { ParsedAddArgv } from "../src/cmd-add.js";
 
 export function addCliArgs(name: string, filePath: string): ParsedAddArgv {
-  return { name, filePath, descriptorPath: null, typesPath: null };
+  return { name, filePath, typesPath: null };
 }