feat(frontend): add API client, layout, and routing

- Create Axios-based API client with sources, jobs, and dashboard endpoints
- Add responsive Layout component with navigation sidebar
- Set up React Router with Dashboard, Backups, and Settings routes
- Configure TanStack Query provider with default options
- Use lucide-react for navigation icons

frontend/node_modules/d3-time-format/locale/pl-PL.json

@@ -0,0 +1,10 @@
+{
+  "dateTime": "%A, %e %B %Y, %X",
+  "date": "%d/%m/%Y",
+  "time": "%H:%M:%S",
+  "periods": ["AM", "PM"],
+  "days": ["Niedziela", "Poniedziałek", "Wtorek", "Środa", "Czwartek", "Piątek", "Sobota"],
+  "shortDays": ["Niedz.", "Pon.", "Wt.", "Śr.", "Czw.", "Pt.", "Sob."],
+  "months": ["Styczeń", "Luty", "Marzec", "Kwiecień", "Maj", "Czerwiec", "Lipiec", "Sierpień", "Wrzesień", "Październik", "Listopad", "Grudzień"],
+  "shortMonths": ["Stycz.", "Luty", "Marz.", "Kwie.", "Maj", "Czerw.", "Lipc.", "Sierp.", "Wrz.", "Paźdz.", "Listop.", "Grudz."]
+}