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>

src/App.tsx

@@ -501,6 +501,10 @@ function App() {
                   <Activity className="w-4 h-4" />
                   Monitor
                 </a>
+                <a href="/financial" className="px-4 py-2 rounded-lg text-zinc-400 hover:text-white hover:bg-white/10 text-sm font-medium transition-all flex items-center gap-2">
+                  <CreditCard className="w-4 h-4" />
+                  Financeiro
+                </a>
               </nav>
 
               <div className="flex items-center gap-3">
@@ -545,6 +549,10 @@ function App() {
                   <Activity className="w-4 h-4" />
                   Monitor
                 </a>
+                <a href="/financial" onClick={() => setMobileMenuOpen(false)} className="px-4 py-3 rounded-lg text-zinc-400 hover:text-white hover:bg-white/10 text-sm font-medium transition-all flex items-center gap-3">
+                  <CreditCard className="w-4 h-4" />
+                  Financeiro
+                </a>
               </div>
             </motion.nav>
           )}