feat: comprehensive SVG viewer enhancements with zoom and template preview

- Add interactive zoom functionality (25%-300% with Ctrl+scroll wheel)
- Fix SVG width constraints by injecting calculated dimensions into templates
- Implement template preview with theme-aware sample data
- Enhance UI layout with file reordering (Project → Template → CSS → Data)
- Add blue theme support for my-project alongside existing green theme
- Fix my-project field mapping from empty 'Übergeordnet' to 'Status'
- Improve SVG viewport handling with proper scrolling and container management
- Add visual zoom controls with percentage display and smart visibility

🤖 Generated with [Claude Code](https://claude.ai/code)

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

my-project/project.json

@@ -10,7 +10,7 @@
   "fieldMapping": {
     "id": "Schlüssel",
     "title": "Zusammenfassung",
-    "lane": "Übergeordnet",
+    "lane": "Status",
     "due": [
       "Abgeleitetes Fälligkeitsdatum",
       "Fälligkeitsdatum"