UI infrastructure and simple "Help" dialog (#3)

Sets up some WIP infrastructure for building out the UI, and adds a simple popup
to show the navigation controls for the app.

framework/project.json

@@ -0,0 +1,24 @@
+{
+  "name": "framework",
+  "$schema": "../node_modules/nx/schemas/project-schema.json",
+  "sourceRoot": "framework/src",
+  "projectType": "library",
+  "targets": {
+    "build": {
+      "executor": "@nx/vite:build",
+      "outputs": ["{options.outputPath}"],
+      "options": {
+        "outputPath": "dist/framework"
+      }
+    },
+    "test": {
+      "executor": "@nx/vite:test",
+      "outputs": ["{options.reportsDirectory}"],
+      "options": {
+        "passWithNoTests": true,
+        "reportsDirectory": "../coverage/framework"
+      }
+    }
+  },
+  "tags": []
+}