Refactor API and enhance Angular integration

- Removed `ciTargetName` from `nx.json`.
- Updated `package.json` to include new dependencies: `@types/seedrandom`, `fast-check`, `happy-dom`, and `@nestjs/schedule`.
- Modified `pnpm-lock.yaml` to reflect the addition of new packages and their versions.
- Improved project documentation in `PROJECT_CONTEXT.md` to clarify the use of Zod schemas and Angular framework decisions.
- Introduced new Angular components and patterns in the `.agents/skills/frontend-angular` directory, including examples and reference materials for Angular 21+ features.

nx.json

@@ -50,7 +50,6 @@
       "plugin": "@nx/vitest",
       "options": {
         "testTargetName": "test",
-        "ciTargetName": "test-ci",
         "testMode": "watch"
       }
     }