fix(workflow): use XcodeGen for iOS app scaffold — prevent SPM executable instead of .xcodeproj (#2041)

Adds ios-scaffold.md reference that explicitly prohibits Package.swift +
.executableTarget for iOS apps (produces macOS CLI, not iOS app bundle),
requires project.yml + xcodegen generate to create a proper .xcodeproj,
and documents SwiftUI API availability tiers (iOS 16 vs 17). Adds iOS
anti-patterns 28-29 to universal-anti-patterns.md and wires the reference
into gsd-executor.md so executors see the guidance during iOS plan execution.

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/ios-scaffold-safety.test.cjs

@@ -0,0 +1,126 @@
+'use strict';
+
+/**
+ * iOS Scaffold Safety Tests (#2023)
+ *
+ * Validates that GSD guidance:
+ * 1. Does NOT instruct using Package.swift + .executableTarget as the primary
+ *    build system for iOS apps (which produces a macOS CLI, not an iOS app).
+ * 2. DOES contain XcodeGen guidance (project.yml + xcodegen generate) for iOS
+ *    app scaffolding.
+ * 3. Documents SwiftUI API availability (iOS 16 vs 17 compatibility).
+ */
+
+const { describe, test } = require('node:test');
+const assert = require('node:assert/strict');
+const fs = require('fs');
+const path = require('path');
+
+const IOS_SCAFFOLD_REF = path.join(
+  __dirname, '..', 'get-shit-done', 'references', 'ios-scaffold.md'
+);
+const EXECUTOR_AGENT = path.join(
+  __dirname, '..', 'agents', 'gsd-executor.md'
+);
+const UNIVERSAL_ANTI_PATTERNS = path.join(
+  __dirname, '..', 'get-shit-done', 'references', 'universal-anti-patterns.md'
+);
+
+describe('ios-scaffold.md reference exists and contains XcodeGen guidance', () => {
+  test('reference file exists at get-shit-done/references/ios-scaffold.md', () => {
+    assert.ok(
+      fs.existsSync(IOS_SCAFFOLD_REF),
+      `Expected iOS scaffold reference at ${IOS_SCAFFOLD_REF}`
+    );
+  });
+
+  test('reference prohibits Package.swift as primary build system for iOS apps', () => {
+    const content = fs.readFileSync(IOS_SCAFFOLD_REF, 'utf-8');
+    const prohibitsPackageSwift =
+      content.includes('Package.swift') &&
+      (
+        content.includes('NEVER') ||
+        content.includes('never') ||
+        content.includes('prohibited') ||
+        content.includes('do not') ||
+        content.includes('Do not') ||
+        content.includes('must not')
+      );
+    assert.ok(
+      prohibitsPackageSwift,
+      'ios-scaffold.md must explicitly prohibit Package.swift as the primary build system for iOS apps'
+    );
+  });
+
+  test('reference prohibits .executableTarget for iOS apps', () => {
+    const content = fs.readFileSync(IOS_SCAFFOLD_REF, 'utf-8');
+    const prohibitsExecutableTarget =
+      content.includes('executableTarget') &&
+      (
+        content.includes('NEVER') ||
+        content.includes('never') ||
+        content.includes('prohibited') ||
+        content.includes('do not') ||
+        content.includes('Do not') ||
+        content.includes('must not')
+      );
+    assert.ok(
+      prohibitsExecutableTarget,
+      'ios-scaffold.md must explicitly prohibit .executableTarget for iOS app targets'
+    );
+  });
+
+  test('reference requires project.yml (XcodeGen spec) for iOS app scaffolding', () => {
+    const content = fs.readFileSync(IOS_SCAFFOLD_REF, 'utf-8');
+    assert.ok(
+      content.includes('project.yml'),
+      'ios-scaffold.md must require project.yml as the XcodeGen spec file'
+    );
+  });
+
+  test('reference requires xcodegen generate command', () => {
+    const content = fs.readFileSync(IOS_SCAFFOLD_REF, 'utf-8');
+    assert.ok(
+      content.includes('xcodegen generate') || content.includes('xcodegen'),
+      'ios-scaffold.md must require the xcodegen generate command to create .xcodeproj'
+    );
+  });
+
+  test('reference documents iOS deployment target compatibility', () => {
+    const content = fs.readFileSync(IOS_SCAFFOLD_REF, 'utf-8');
+    const hasApiCompatibility =
+      content.includes('iOS 16') ||
+      content.includes('iOS 17') ||
+      content.includes('deployment target') ||
+      content.includes('NavigationSplitView') ||
+      content.includes('availability') ||
+      content.includes('SwiftUI API');
+    assert.ok(
+      hasApiCompatibility,
+      'ios-scaffold.md must document SwiftUI API availability and iOS deployment target compatibility'
+    );
+  });
+});
+
+describe('gsd-executor.md references ios-scaffold guidance', () => {
+  test('executor agent references ios-scaffold.md', () => {
+    const content = fs.readFileSync(EXECUTOR_AGENT, 'utf-8');
+    assert.ok(
+      content.includes('ios-scaffold.md') || content.includes('ios-scaffold'),
+      'gsd-executor.md must reference ios-scaffold.md for iOS app scaffold guidance'
+    );
+  });
+});
+
+describe('universal-anti-patterns.md documents iOS SPM anti-pattern', () => {
+  test('universal-anti-patterns.md documents Package.swift misuse for iOS apps', () => {
+    const content = fs.readFileSync(UNIVERSAL_ANTI_PATTERNS, 'utf-8');
+    const hasAntiPattern =
+      (content.includes('Package.swift') || content.includes('SPM')) &&
+      (content.includes('iOS') || content.includes('ios'));
+    assert.ok(
+      hasAntiPattern,
+      'universal-anti-patterns.md must document the Package.swift/SPM misuse anti-pattern for iOS apps'
+    );
+  });
+});