chore: scaffold SPFx solution with ui-kit

Clean SPFx 1.22 (heft) web part template with @tnsu/ui-kit wired in.
Starting point for merging the stroy-bot-* repositories.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

config/sass.json

@@ -0,0 +1,4 @@
+{
+  "$schema": "https://developer.microsoft.com/json-schemas/heft/v0/heft-sass-plugin.schema.json",
+  "extends": "@microsoft/spfx-web-build-rig/profiles/default/config/sass.json"
+}