feat: init workspace generates bundle script (#216 Phase 1)

- Add scripts.bundle to generated package.json
- Generate scripts/bundle.ts that scans workflows/*-entry.ts,
  uses Bun.build() to produce dist/*.esm.js + dist/*.d.ts
- External: @uncaged/workflow-* packages (per bundle contract)
- Add tests for new scaffold files

Testing: #217
Ref: #216

packages/cli-workflow/__tests__/init-workspace.test.ts

@@ -38,8 +38,16 @@ describe("init workspace", () => {
 
     const rootPkg = JSON.parse(await readFile(join(root, "package.json"), "utf8")) as {
       workspaces: string[];
+      scripts: { bundle: string };
     };
     expect(rootPkg.workspaces).toEqual(["templates/*", "workflows"]);
+    expect(rootPkg.scripts.bundle).toBe("bun run scripts/bundle.ts");
+
+    expect(await pathExists(join(root, "scripts", "bundle.ts"))).toBe(true);
+    const bundleSrc = await readFile(join(root, "scripts", "bundle.ts"), "utf8");
+    expect(bundleSrc).toContain("Bun.build");
+    expect(bundleSrc).toContain("-entry.ts");
+    expect(bundleSrc).toContain("distDir");
 
     const wfPkg = JSON.parse(await readFile(join(root, "workflows", "package.json"), "utf8")) as {
       type: string;