Method update

crates/opencode-tui/src/ui/selection.rs:38–42

Update the drag endpoint.

(&mut self, row: u16, col: u16)

    /// Update the drag endpoint.
    pub fn update(&mut self, row: u16, col: u16) {
        if self.dragging {
            self.cursor = Some((row, col));
        }
    }

    /// Mouse button released — keep the selection visible but stop tracking.
    pub fn finalize(&mut self) {