.ai import: symbol libraries open with their symbols

A .ai or EPS whose editing data defines symbols but has no layers came
in as its PDF part or page without symbols, and Other Library in the
Symbols panel listed none. Such a file, and a file read as its PDF part
or page because its layers can't be used, now gets the symbols its
editing data defines before its first layer, as a file read from its
layers does: File > Open shows them in the Symbols panel in the order
of the symbol list, and Other Library lists them in a library panel.

- Each symbol keeps its registration point. A symbol that holds an
  instance of a symbol the file doesn't define is left out, and an
  object linked to a listed graphic style keeps the link.
- The symbols' art takes ids of the document, the art of opacity masks
  in it included, and the images it shows come with it. Instances
  drawn too deep are removed with the usual note.
- The global and spot colors the art is linked to come in as swatches.
  A color whose name another swatch has takes that swatch's place when
  it is a default swatch of a file without a palette; otherwise it
  comes in under a free variant of the name ("Ink 2"), which the art
  then names.
- Symbol art keeps the editing data's units, as in a file read from its
  layers, so in a file in larger units its linked graphic styles are
  drawn at the scaled size and the symbol art is not.
- The art of the patterns a palette or brush brings into a file read as
  its PDF part or page now also takes new ids for its opacity masks.

Part of #3349

docs/mcp.md

@@ -2378,7 +2378,9 @@ what dragging a symbol out of the library panel onto the canvas does.
 `symbol.saveLibrary {path?, names?, name?, user?}` writes the document's symbols as a symbol library: a `.vectorcraft`
 document holding only them and what they use; without `path` it returns `{dataBase64}`, and `user: true` saves into
 the user library folder (category `user`, User Defined). `symbol.loadLibrary {path? | data? | dataBase64?, name?}`
-loads the symbols of any document VectorCraft opens as a library to add from; a file it can't read is an error.
+loads the symbols of any document VectorCraft opens as a library to add from (a `.ai` or EPS whose editing data holds
+symbols and no layers gives the symbols it defines, in the order of its symbol list); a file it can't read is an
+error.
 
 ## Brush libraries
 

docs/target-app-parity.md

@@ -1222,6 +1222,7 @@ Moved from the ROADMAP's "Shipped so far" on 2026-10-10. Update it when a featur
     In a `.ai` or EPS opened from its editing data, type has its text object's opacity, blend mode and knockout shape flag, whether it is made from the file's text document or taken from the page, and type made from the text document takes its text object's lock. Where such type has transparency and comes in with other art (the rest of its look, or page type and strokes that go with it), a group of them has it. Where the page draws its type, or the strokes around it, with transparency that is neither its text object's nor its text object's combined with that of the objects around it, the page's type and strokes keep their own instead (`crates/eps/src/import/tests_native.rs`). Where the page draws type of no text object over text objects made from the text document, with their words in any case, that type is theirs as the page draws it and is left out; the page's other type of no text object goes only to text objects whose type the text document can't make, or else is left out with a warning.
     `.ai` editing-data import restores the document's listed graphic styles in panel order and links objects that use a listed style; unsupported appearances keep their drawn look (`crates/eps/src/import/ai/tests.rs`).
     A `.ai` or EPS graphic style library, whose editing data holds the styles and their list but no layers, opens with those styles in list order. Other Library… loads another document's graphic styles ([Apply graphic styles](https://helpx.adobe.com/illustrator/desktop/special-effects-styles/apply-graphic-styles/apply-graphic-styles.html)) and lists such a library's styles in a library panel. A `.ai` or EPS read as its PDF part or page because its layers can't be used also gets the styles of its list in place of the default ones (`crates/eps/src/import/tests_native.rs`, `cmd::fileio::tests_aiimport::a_graphic_style_library_in_a_ai_file_without_layers_loads_its_styles`).
+    A `.ai` or EPS symbol library, whose editing data holds symbol definitions and their list but no layers, opens with those symbols in list order, each with its registration point. Other Library… in the Symbols panel's Symbol Libraries Menu imports the symbols of the file you pick ([Create or import symbol libraries](https://helpx.adobe.com/illustrator/desktop/manage-objects/traces-mockups-symbols/create-or-import-symbol-libraries.html)) and lists such a library's symbols in a library panel. A `.ai` or EPS read as its PDF part or page because its layers can't be used also gets the symbols defined before its layers (`crates/eps/src/import/tests_native.rs`, `crates/eps/src/import/ai/tests.rs`, `cmd::fileio::tests_aiimport::a_symbol_library_in_a_ai_file_without_layers_loads_its_symbols`).
     A `.ai` or EPS opened from its editing data whose text document makes the type of every text object that shows takes all its type from the text document: each text object stays in its own group, frame and layer, the page's type isn't matched with them, a file of more than 5,000 text objects still opens with its layers, and type the page draws differently (in another font) keeps the layers, with a warning. A line break inside a paragraph stays a line break in it (`crates/eps/src/import/tests_native.rs`, `crates/eps/src/import/ate.rs`).
     In SVG export without Fewer `<tspan>` Elements, each character of live type that justification or Mojikumi moves (the letter gaps of a Justify All line without word spaces, the gaps between the characters of a justified Japanese line, closed-up punctuation, the space between Japanese and Latin letters) starts its own positioned `<tspan>`, and type scaled horizontally on a justified line is stretched to its own width (`crates/svg/tests/it/text_layout.rs`).
     To find those characters, SVG export lays a type object out a second time only when the second layout can differ from the first: point type with Line-end Punctuation Half Width and no Japanese punctuation or letters, the setting new type gets, is laid out once. Exporting 5,000 such objects takes a median of 109.4 ms instead of 171.5 ms on Windows 11, with the same SVG (`crates/svg/src/export/text/tests.rs`).