add and delete sections

[LaSi5002]

No description provided.

[Copilot]

Pull Request Overview

This PR adds functionality to add and delete sections in the web viewer interface. It introduces UI controls for managing sections dynamically, including an autocomplete field for adding new sections and a delete button for removing existing ones.

• Adds a new top row layout with edit mode switch and section addition controls
• Implements backend handlers for adding and deleting sections with proper state management
• Updates the section dropdown visibility logic to handle cases where main and selected sections differ

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
src/fourc_webviewer/gui_utils.py	Adds _top_row function with add section controls, moves edit mode switch, adds delete section button, and updates dropdown visibility logic
src/fourc_webviewer/fourc_webserver.py	Implements click_delete_section_button and change_add_section handlers with state initialization for the add section feature

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[dragos-ana]

Nice work! I added some suggestions, feel free to ask if something is unclear