feat: add AI command suggestions extension for Tiptap editor

- Implemented Commands plugin to handle command suggestions triggered by '@' character.
- Created suggestion configuration to filter and render command items.
- Added various command items including date, time, formatting, templates, and task management commands.
- Introduced CSS styles for the Tiptap editor to enhance UI.
- Configured TypeScript settings and Vite build for the project.

.gitignore

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+.env
+!.env*development
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+node_modules
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+dist
+pack-dist
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+.DS_Store
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+.pnpm-store
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+.vite
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+.astro