feat: port all template categories to JSON format

- Ported Minimalist templates to JSON (Swiss Grid, Brutalist, etc.)
- Ported Tech templates to JSON (SaaS, Terminal, Cyberpunk, etc.)
- Ported Creative templates to JSON (Art Gallery, Zine, Pop Art, etc.)
- Ported Industrial templates to JSON (Blueprint, Factory, Schematic, etc.)
- Ported Nature templates to JSON (Botanical, Ocean, Mountain, etc.)
- Ported Lifestyle templates to JSON (Cookbook, Travel, Coffee House, etc.)
- Ported Vintage templates to JSON (Art Deco, Medieval, Retro 80s, etc.)
- Updated README.md to reflect the new JSON-based style system (example configuration and contribution workflow)
- Completed migration of over 150 styles to the new architecture

validate_json.ps1

@@ -0,0 +1,13 @@
+$templatesDir = "d:\gdfhbfgdbnbdfbdf\typogenie\src-tauri\templates"
+$files = Get-ChildItem -Path $templatesDir -Recurse -Filter *.json
+
+foreach ($file in $files) {
+    try {
+        $content = Get-Content -Path $file.FullName -Raw
+        $json = $content | ConvertFrom-Json
+        Write-Host "VALID: $($file.Name)" -ForegroundColor Green
+    } catch {
+        Write-Host "INVALID: $($file.Name)" -ForegroundColor Red
+        Write-Host "Error: $($_.Exception.Message)"
+    }
+}