Add multi tag filter

[NirSikron]

This PR adds the ability to filter repositories by multiple tags instead of just one. In addition, clicking again on an already selected tag will deselect it.

Changes made:

• Added reactive selectedTags array to manage selected filters.
• Clicking a tag toggles it on/off.
• Updated sidebar logic and added a TODO for filtering logic in main list.
• Confirmed UI changes and state behavior locally.

Let me know if any improvements are needed 🙌

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This is my first open-source contribution – happy to be part of the project! 😊