sync: contextual substrate UX from private repo

- Add DimensionIconsContext for app-wide dimension icon sharing
- Enhanced getNodeIcon() with favicon/YouTube/PDF detection + dimension icons
- Propagate dynamic icons to GridView, ListView, SearchModal, FocusPanel, ViewsOverlay, FolderViewOverlay
- Add RahEdge component with hover labels for map edges
- Update RahNode with dimension-colored borders and icon support
- Add MiniMap with dimension color coding to MapPane
- MCP server: add description field to rah_update_node, bump standalone to v1.4.2

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/mcp-server-standalone/package.json

@@ -1,6 +1,6 @@
 {
   "name": "ra-h-mcp-server",
-  "version": "1.4.1",
+  "version": "1.4.2",
   "description": "Connect Claude Code/Desktop to your RA-H knowledge base. Direct SQLite access - no web app required.",
   "main": "index.js",
   "bin": {