feat: wire guide data source and POI focus UI

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/domain/guideModel.ts

@@ -0,0 +1,26 @@
+export interface GuideRenderPoi {
+  id: string
+  name: string
+  floorId: string
+  primaryCategory: string
+  primaryCategoryZh: string
+  iconType: string
+  positionGltf?: [number, number, number]
+}
+
+export interface GuideModelFloorAsset {
+  floorId: string
+  label: string
+  order: number
+  modelUrl: string
+}
+
+export interface GuideModelRenderPackage {
+  overviewModelUrl: string
+  floors: GuideModelFloorAsset[]
+}
+
+export interface GuideModelSource {
+  loadPackage(): Promise<GuideModelRenderPackage>
+  loadFloorPois(floorId: string): Promise<GuideRenderPoi[]>
+}