Reusable custom colour palettes (save, name, and reuse across patterns)

Today you can save a palette to a file and load it back (colors panel → Palette Tools), keep multiple colorways per pattern, and hand-build a custom palette in the image-import Colors step. What's missing is a named palette library tied to your account rather than to a file on disk — and the import wizard can't load a saved palette file, so "convert this photo using only the threads I own" isn't possible. Note for implementation: PaletteStore already has full CRUD + localStorage persistence; this is mostly a management UI.