fix(ui): Add visible cursor to filter input

[damacus]

💡 What: Added a visible blinking terminal cursor to the tag FilterInput mode in the TUI.
🎯 Why: When filtering runners by tags, typing into the filter input box had no visual indicator of where the cursor was located or the state of the text input. This lacked immediate interaction feedback, making the UI less intuitive and potentially confusing for keyboard users.
📸 Before/After: Before, typing in the filter input was "blind". Now, a block cursor is positioned at the end of the text buffer.
♿ Accessibility: Improves keyboard interaction accessibility by providing a clear, standard visual focus indicator when the filter input is active.

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PR created automatically by Jules for task 2011865889959246615 started by @damacus

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