feat: add element-inspector

- Implemented Rulers component for zoom/pan-aware rulers on canvas.
- Created Stage component to serve as a zoomable and pannable viewport for the device frame.
- Developed Toolbar component for responsive controls, including device presets and zoom functionalities.
- Introduced useFrame composable to manage iframe interactions and inspections.
- Established a reactive store to manage application state, including guides and viewport dimensions.
- Added utility functions for color parsing and box model calculations.
- Integrated Tailwind CSS for styling and improved scrollbar aesthetics.
- Implemented unit tests for color utilities and rectangle calculations.
- Configured TypeScript and Vite for the project setup.

element-inspector/.gitignore

@@ -0,0 +1,4 @@
+node_modules
+dist
+*.log
+.DS_Store