refactor: extract UI from ImageShowTool into separate component

fix: unify error message to "Failed to fetch" and exit on load failure

feat: add loadImageFromUrl helper and wire it into LocalPicture test

feat(LocalPicture): support CLI args for path/URL and golden ratio width

feat: pass pixelWidth/pixelHeight from Image props to Kitty renderer

fix: reduce blank rows below Kitty images by using placement c=/r= bounds

fix: preserve image aspect ratio with cover() and dynamic height calculation

fix: add Ghostty env-var detection for Kitty graphics in ink-picture

feat: add useStdout and useIsScreenReaderEnabled hooks for ink-picture

refactor: integrate ink-picture as source directory