Refactor to multi-category catalog with polished light mode

- Restructure from single filament table to multi-category product catalog
  (filamenti, stampaci, ploce, mlaznice, delovi, oprema)
- Add shared layout components (SiteHeader, SiteFooter, CategoryNav, Breadcrumb)
- Add reusable UI primitives (Badge, Button, Card, Modal, PriceDisplay, EmptyState)
- Add catalog components (CatalogPage, ProductTable, ProductGrid, FilamentCard, ProductCard)
- Add admin dashboard with sidebar navigation and category management
- Add product API endpoints and database migrations
- Add SEO pages (politika-privatnosti, uslovi-koriscenja, robots.txt, sitemap.xml)
- Fix light mode: gradient text contrast, category nav accessibility,
  surface tokens, card shadows, CTA section theming

database/migrations/022_create_printer_compatibility.sql

@@ -0,0 +1,25 @@
+-- Migration: Create printer models and product compatibility junction table
+
+CREATE TABLE printer_models (
+  id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+  name VARCHAR(100) NOT NULL UNIQUE,
+  series VARCHAR(50) NOT NULL
+);
+
+CREATE TABLE product_printer_compatibility (
+  product_id UUID REFERENCES products(id) ON DELETE CASCADE,
+  printer_model_id UUID REFERENCES printer_models(id) ON DELETE CASCADE,
+  PRIMARY KEY (product_id, printer_model_id)
+);
+
+-- Seed printer models
+INSERT INTO printer_models (name, series) VALUES
+  ('A1 Mini', 'A'),
+  ('A1', 'A'),
+  ('P1P', 'P'),
+  ('P1S', 'P'),
+  ('X1C', 'X'),
+  ('X1E', 'X'),
+  ('H2D', 'H'),
+  ('H2S', 'H'),
+  ('P2S', 'P');