feat(export): default-view option, Cyrillic PDF, per-wall projection pages

- Add 'Default View' scope to PNG export (fit-to-room for 2D, birds-eye for 3D)
- PDF now includes 3D top view, 2D default view, and every wall projection
- Embed DejaVu Sans TTF so Cyrillic room names render correctly in PDFs
- Preserve image aspect ratios and top-align on PDF pages
- Render each wall projection on its own PDF page at native aspect
- Mount a hidden per-wall projection renderer during export so all walls
  are captured even when the visible panel is in tab mode
- Keep 3D view mounted off-screen once requested so PDF can always snap
  to birds-eye without a visible view switch
- Outlet projection coordinate labels now show 3 decimal places

apps/client/package.json

@@ -14,6 +14,7 @@
     "@house-plan-maker/shared": "*",
     "@react-three/drei": "^10.7.7",
     "@react-three/fiber": "^9.5.0",
+    "dejavu-fonts-ttf": "^2.37.3",
     "i18next": "^26.0.3",
     "i18next-browser-languagedetector": "^8.2.1",
     "jspdf": "^4.2.1",