Make texture and colour full kinds and drop the load-time migrations

- `Texture` and `Color` can be picked as a variable kind, a struct field
  kind and a declared port kind; a new `Texture` node hands a picture id
  into the graph. Declared, a texture is its bare id – the `$texture` tag
  stays a list-only thing.
- The `String` node is labelled "Text" like its kind; the type id stays.
- Whole-number inputs (`Item at`, `Set item`, `Sub list`, `Fill`,
  `Repeat`, `Substring`, `To text`) show no decimals (`int()` in shared.ts).
- All server projects are reseeded, so `legacyNodes.ts`,
  `migrateDeclaredLists` and the `ownerId` fallback go, with their tests.
- Note `reseed-because-of-list` moved to done/; new note `refactor-types`.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

src/core/model/Properties.ts

@@ -1,8 +1,8 @@
 /** Depth is capped: `list → struct → primitive` is the deepest a stored value goes. */
 export type ListValue = readonly (number | string | boolean | StructValue)[];
 
-/** What a struct field may hold. A field is never itself a struct – except a tagged colour. */
-export type FieldValue = number | string | boolean | ListValue | ColorItem;
+/** What a struct field may hold. A field is never itself a struct – except a tagged colour or texture. */
+export type FieldValue = number | string | boolean | ListValue | ColorItem | TextureItem;
 
 /** Several named values travelling as one, so a bundle needs one port instead of one per part. */
 export type StructValue = { readonly [field: string]: FieldValue };