This commit completes the migration of the GCodeViewer UI from jQuery and
jQuery UI to a modern Svelte-based component architecture.

Key changes include:

- **Svelte Environment:** Introduced Svelte, Rollup for building, and a new
  project structure under `src/` for Svelte components and `public/` for
  the application entry point (`public/index.html`).

- **Component-Based UI:** Reimplemented all major UI elements as Svelte
  components, including:
    - Accordions, Tabs, Sliders (vertical and horizontal)
    - Modals, Dropdowns, Buttons, Progress Bars
    - File Uploader (with drag & drop)
    - Information display panels (ModelInfo, LayerInfo)
    - Options panels (2D Render, Analyzer, Printer Info)
    - Notification system
    - CodeMirror integration for G-code preview

- **Application Orchestration:** `App.svelte` serves as the main application
  component, managing state, component interactions, and communication with
  the original G-code processing logic.

- **jQuery Removal:**
    - All direct jQuery DOM manipulations and event handling in `js/ui.js`
      have been replaced with Svelte's reactive mechanisms.
    - `js/ui.js` is no longer used or loaded.
    - Script tags for `jquery`, `jquery-ui`, and `bootstrap.js` (jQuery
      dependent) have been removed from the main HTML.
    - CSS for jQuery UI has been removed. (Bootstrap CSS is retained for
      general styling).

- **Integration:** The Svelte application now loads the original G-code
  processing scripts (`gCodeReader.js`, `renderer.js`, etc.) and interacts
  with them via the global `GCODE` object. I handle G-code analysis communication within `App.svelte`.

- **Modernization:** Includes improved accessibility in some components and
  a more maintainable, reactive codebase. Browser capability checks are
  performed on load, with notifications for missing features.

This refactoring aims to improve the maintainability, performance, and
developer experience of the GCodeViewer frontend.