Remove inline Edit button; enable horizontal scrolling in todo list

[multiplex55]

Motivation

• Make editing explicit via the context menu and allow long todo text to overflow horizontally so users can scroll instead of forcing line wraps.

Description

• Removed the inline Edit button and its click handler so entries are edited only via the Edit Todo context menu.
• Replaced ui.horizontal_wrapped with ui.horizontal and enabled bi-directional scrolling using egui::ScrollArea::both().auto_shrink([false, false]) so horizontal overflow is preserved.
• Applied .wrap(false) to ui.label(...) calls for todo text, priority, and tags and added a comment documenting the expected horizontal scroll behavior.

Testing

• No automated tests were run; the change is documented with an inline comment instead of adding a UI unit test.

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Codex Task