Hardcoded Year 2025 in Project Health Dashboard Monthly Trend Chart

### Describe the bug
The Project Health Dashboard's monthly trend LineChart uses a hardcoded year (`2025`) when constructing dates for month labels.

This causes:
- Incorrect year display after December 2025
- Wrong dates when viewing historical or future data
- Maintenance issues due to non-dynamic date logic

Currently, the year does not adapt based on real time or dataset values.

---

### To Reproduce

Steps to reproduce the behavior:

1. Go to Project Health Dashboard
2. Open the monthly trend LineChart
3. Inspect the month labels or date formatting
4. Notice that all dates are generated using year **2025**, regardless of current or selected year

Code reference:
```ts
// frontend/src/app/projects/dashboard/page.tsx (Line ~135)
const date = new Date(2025, month - 1, 1) // hardcoded year
```

**Expected behavior**
The year should be dynamically calculated

**Are you going to work on fixing this?**
- [x] Yes
- [ ] No

**Desktop (please complete the following information):**
- OS: Windows 11
- Browser: Chrome
- Version: Latest