fix(input): handle 'auto' width in tag-input to prevent line breaks

[Copilot]

Multi-select components with pre-filled tags sometimes render with width: auto on the internal input, causing unwanted line breaks.

Changes

packages/components/input/hooks/useInputWidth.ts

• Check for 'auto' or '' from getComputedStyle
• Set to '0px' instead of applying invalid width value
• Prevents input from consuming space in tag layouts

const computedWidth = getComputedStyle(inputPreRef.value).width;
if (computedWidth === 'auto' || computedWidth === '') {
  inputRef.value.style.width = '0px';
} else {
  inputRef.value.style.width = computedWidth;
}

Affects autoWidth behavior in tag-input/select-input components when tags are present.