* Add Svelte support and interactive chat mock UI

Integrates Svelte into the Astro project by adding @astrojs/svelte and related dependencies, updating configuration files, and introducing a mock Chat.svelte component. Adds a new interactive-help.astro page that renders the chat UI, preparing for future WebLLM integration.

* Add prettier-plugin-svelte and update code formatting

Added prettier-plugin-svelte to devDependencies for improved Svelte formatting. Updated codebase to use consistent double quotes and improved formatting in Astro and Svelte config files, as well as minor whitespace and formatting adjustments in markdown and Astro files for consistency.

* Refactor Chat UI to use English and simplify logic

Refactored Chat.svelte to use English for UI text and comments, simplified message creation with a helper function, and improved code readability. Updated placeholder and button text, and streamlined the mock response logic. Minor formatting adjustments were made in index.astro for consistency.

* Integrate WebLLM with Svelte chat UI and preload FAQ

Added @mlc-ai/web-llm as a dependency and introduced llm.ts to manage LLM state and initialization in Svelte. Refactored Chat.svelte to use WebLLM for assistant responses, including streaming support, user consent for model download, and FAQ knowledge base preloading as a system prompt. Improved UI to handle LLM loading states, errors, and user interaction for model initialization.

* Refactor Chat UI and add English localization

Rewrote comments and UI text in Chat.svelte from Japanese to English, removed the FAQ preloading logic, and improved the system prompt for clearer assistant behavior. Updated interactive-help.astro to add a 'Back to the top page' link and use environment-based URL joining. These changes enhance clarity, maintainability, and user experience for English-speaking users.

* Add interactive help entry point and disclaimers

Introduces a prominent 'Ask Anything (Experimental)' button on the homepage linking to the interactive help chat. Updates the initial assistant greeting in Chat.svelte for a more welcoming tone. Adds experimental, privacy, and accuracy disclaimers to the interactive help page for user awareness.

* Revise FAQ and improve OS install instructions

The FAQ.md was rewritten to focus on concise, LLM-friendly installation Q&A for all supported platforms, replacing the previous 50-question format. The Ubuntu, Flatpak, and Windows install pages were updated to use the <Code> component for command snippets and now provide clearer, step-by-step instructions. The Ubuntu page now dynamically fetches the latest .deb asset and offers both GUI and terminal install options. The macOS page was mistakenly updated to reference the Ubuntu .deb asset instead of the correct macOS package, which should be reviewed.

* Refactor Chat UI and update LLM model version

Improves code style and formatting across Svelte and Astro components, enhances the Chat UI for better streaming and error handling, and updates the default LLM model to Llama-3.2-1B-Instruct-q4f16_1-MLC. Also adds Svelte support to Prettier config and applies consistent code formatting to installation instructions.

* Update llm.ts

* Update FAQ.md

* Update FAQ.md

* Update FAQ.md

* Update Chat.svelte