feat: add financial panel, compact services list, add Syncthing

- New /financial page with sales/expenses cards, monthly bar chart and
  expense distribution pie chart (Recharts)
- New API endpoint GET /api/financial with queries on tblinvoices and
  tblexpenses
- Compact services grid (2-col dots layout) in Monitor page
- Add Syncthing to critical services monitoring
- Add Financeiro nav link to Dashboard, Monitor and Financial headers

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

api/routes/financial.ts

@@ -0,0 +1,22 @@
+/**
+ * Financial API Route
+ * GET /api/financial
+ * @author Descomplicar® | @link descomplicar.pt | @copyright 2026
+ */
+import { Router } from 'express'
+import type { Request, Response } from 'express'
+import { getFinancialData } from '../services/financial.js'
+
+const router = Router()
+
+router.get('/', async (_req: Request, res: Response) => {
+  try {
+    const data = await getFinancialData()
+    res.json(data)
+  } catch (error) {
+    console.error('Financial API error:', error)
+    res.status(500).json({ error: 'Internal server error' })
+  }
+})
+
+export default router