Add guided tour feature with Driver.js

- Install driver.js package for lightweight product tours
- Create GuidedTour component with bilingual tour steps (Chinese/English)
- Create TourPromptModal to ask users if they want a tour after welcome
- Add data-tour attributes to Toolbar, FilePanel, PedigreeCanvas, PropertyPanel
- Tour covers: file operations, adding persons, canvas usage, relationships,
  editing properties, and exporting

Tour flow:
1. First visit: Welcome Modal → Tour Prompt Modal → Start tour or skip
2. Subsequent visits: No modals shown

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

package-lock.json

@@ -9,6 +9,7 @@
       "version": "0.0.0",
       "dependencies": {
         "d3": "^7.9.0",
+        "driver.js": "^1.4.0",
         "html-to-image": "^1.11.13",
         "react": "^19.2.0",
         "react-dom": "^19.2.0",
@@ -2672,6 +2673,12 @@
         "robust-predicates": "^3.0.2"
       }
     },
+    "node_modules/driver.js": {
+      "version": "1.4.0",
+      "resolved": "https://registry.npmjs.org/driver.js/-/driver.js-1.4.0.tgz",
+      "integrity": "sha512-Gm64jm6PmcU+si21sQhBrTAM1JvUrR0QhNmjkprNLxohOBzul9+pNHXgQaT9lW84gwg9GMLB3NZGuGolsz5uew==",
+      "license": "MIT"
+    },
     "node_modules/electron-to-chromium": {
       "version": "1.5.267",
       "resolved": "https://registry.npmjs.org/electron-to-chromium/-/electron-to-chromium-1.5.267.tgz",