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/style.css

@@ -1 +1,64 @@
-body { background:#f5f7fa; }
+/* My Project Blue Theme */
+/* This CSS demonstrates successful external stylesheet loading */
+
+body {
+  background: #1a2332 !important;
+}
+
+#projectName {
+  color: #3b82f6 !important;
+  border-bottom: 2px solid #3b82f6;
+  padding-bottom: 8px;
+}
+
+#projectSubtitle {
+  color: #60a5fa !important;
+}
+
+/* File Manager Override */
+#fileManager {
+  background: #1e293b !important;
+  border-color: #3b82f6 !important;
+}
+
+#fileManager h3 {
+  color: #60a5fa !important;
+}
+
+.file-item {
+  background: #334155 !important;
+  border-color: #3b82f6 !important;
+}
+
+.file-item:hover {
+  border-color: #60a5fa !important;
+  box-shadow: 0 2px 8px rgba(59, 130, 246, 0.2) !important;
+}
+
+.file-label {
+  color: #60a5fa !important;
+}
+
+.upload-btn {
+  background: #3b82f6 !important;
+}
+
+.upload-btn:hover {
+  background: #2563eb !important;
+}
+
+/* Buttons */
+button {
+  background: #3b82f6 !important;
+}
+
+button:hover:not(:disabled) {
+  background: #60a5fa !important;
+}
+
+/* Viewer */
+#viewer {
+  background: #334155 !important;
+  border-color: #3b82f6 !important;
+  color: #f1f5f9 !important;
+}