Story 4.1: Task 1 Complete - PlayerPrivacyManager Core Logic

- Created src/contracts/privacy-settings.js with:
  - PrivacySettings typedef
  - PRIVACY_SETTINGS_DEFAULT (both flags false)
  - PRIVACY_SETTING_KEYS and FEATURE_NAME_MAP constants
  - createPrivacySettings() factory
  - isValidPrivacySettings() validator
  - validateSettingKey(), validateSettingValue(), validateFeatureName() helpers
- Created src/core/PlayerPrivacyManager.js with:
  - Constructor with FoundryAdapter DI validation
  - getSettings(userId) - retrieves settings from user flags
  - setSetting(userId, key, value) - async, validates, persists via user.setFlag
  - isOptedIn(userId, feature) - convenience method for feature checks
  - getAllSettings() - aggregates all users' settings (GM view)
  - onChange(callback) - subscription pattern for change events
  - teardown() - cleanup
- Created tests/unit/contracts/privacy-settings.test.js - 44 tests
- Created tests/unit/core/PlayerPrivacyManager.test.js - 35 tests
- All tests passing, lint clean
- Updated sprint-status.yaml: 4-1 from ready-for-dev to in-progress
- Updated story file: Task 1 subtasks 1.1-1.8 marked complete

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>

package.json

@@ -14,6 +14,7 @@
   },
   "devDependencies": {
     "@league-of-foundry-developers/foundry-vtt-types": "9.280.1",
+    "@playwright/test": "^1.60.0",
     "@types/node": "22.x",
     "chokidar": "5.0.0",
     "eslint": "^9.0.0",