Update packages and tests (#60)

### 🔧 Dependency Maintenance & React Flow Migration

**Summary**
This PR performs essential dependency maintenance, primarily migrating
the deprecated `reactflow` library to its successor `@xyflow/react` and
fixing testing configurations to align with updated tooling.

**Key Changes**

**1. React Flow Migration**
- Replaced `reactflow` (v11) with `@xyflow/react` (v12) throughout the
application.
- Updated imports in
[technique-node.tsx](cci:7://file:///home/parallels/Documents/antigravity-testing/rtap/src/features/operations/components/attack-flow/technique-node.tsx:0:0-0:0)
and
[attack-flow/index.tsx](cci:7://file:///home/parallels/Documents/antigravity-testing/rtap/src/features/operations/components/attack-flow/index.tsx:0:0-0:0).
- Updated CSS import to `@xyflow/react/dist/style.css`.
- **Type Fixes**: Resolved strict TypeScript errors exposed by the new
library version (e.g., ensuring Node data satisfies `Record<string,
unknown>`).

**2. Test Configuration**
- Fixed
[vitest.config.ts](cci:7://file:///home/parallels/Documents/antigravity-testing/rtap/vitest.config.ts:0:0-0:0)
breakage caused by Vitest upgrades. replaced the deprecated
`poolOptions` with `fileParallelism: false` to ensure stable,
single-threaded database testing.

**3. General Updates**
- Verified `zod` compatibility (v4 check).
- confirmed `npm audit` is clean after updates.

**Testing**
- Verified `npm run check` (TypeScript/ESLint) passes.
- Verified `npm run test` passes (49/49 test suites).
- Manual check: Attack Flow visualization loads correctly with new
library.

Author: initstring