refactor: migrate role handling from tiers to roles module

- Removed the deprecated tiers.ts file and migrated all related functionality to roles/index.js.
- Updated tests and tools to reflect the new role structure, replacing references to "dev", "qa", and "architect" with "developer", "tester", and "architect".
- Adjusted workflow configurations and state management to accommodate the new role naming conventions.
- Enhanced project registration and health check tools to support dynamic role handling.
- Updated task creation, update, and completion processes to align with the new role definitions.
- Improved documentation and comments to clarify role responsibilities and usage.

package.json

@@ -53,5 +53,8 @@
   "devDependencies": {
     "@types/node": "^25.2.3",
     "typescript": "^5.9.3"
+  },
+  "dependencies": {
+    "yaml": "^2.8.2"
   }
 }