refactor(ImageShowTool): download URLs to temp file, fix concurrency for kitty protocol

fix(ImageShowTool): use terminal height instead of width for dimension calculation

fix(ImageShowTool): simplify dimensions — use height as primary, compute width from aspect ratio

fix(ImageShowTool): read local file to buffer before Jimp.read

feat(ImageShowTool): use timg for full-res Kitty image, dedup placement

refactor: move ink-picture rendering from call() to UI React tree

fix: make ImageShowTool non-deferred so model can discover and call it

feat: integrate ink-picture rendering into ImageShowTool, remove InlineImage

feat: register ImageShowTool as a proper buildTool with prompt + UI

refactor: extract UI from ImageShowTool into separate component

refactor: extract UI from ImageShowTool into separate component

refactor: rewrite ImageShowTool with new architecture