.ai import: open the variable library and data sets from the editing data

Squashed from #5156 onto main.

docs/mcp.md

@@ -1654,7 +1654,9 @@ already walks Image Trace. Short agent entry points:
   `variable.define`, `variable.delete`, `variable.rename`, the four `variable.make…Dynamic` commands and a
   `variable.loadLibrary` that would delete or define a variable (below) fail with "variables are locked";
   `variable.bind`, `variable.unbind` and the `dataset.*` commands still run (except a `dataset.import` whose header
-  would define a variable, below), and `variable.list` reports `locked`.
+  would define a variable, below), and `variable.list` reports `locked`. A variable that an opened `.ai` declares
+  without a kind VectorCraft reads is listed with `kind: "unknown"`: it takes no values, and `variable.bind`
+  refuses it.
 - Data sets: `dataset.list`, `dataset.new {name, values?}`, `dataset.set {name, newName?, values?}` (`newName` also
   renames the row, in the same undo step; Edit Data Set's Name field sends it), `dataset.rename`,
   `dataset.delete`, `dataset.capture`, `dataset.update`, `dataset.select {name}`, `dataset.next` /

docs/target-app-parity.md

@@ -1094,7 +1094,7 @@ Moved from the ROADMAP's "Shipped so far" on 2026-10-10. Update it when a featur
     A PDF saved with Illustrator's editing data opens through it as a PDF-compatible `.ai` does, with its layers and groups and with art reaching past its page unclipped; such a PDF holds the data in `AIPDFPrivateData` streams (part of #868). A shape a PDF or `.ai` paints with a gradient (a clip path round a shading) opens as one path filled with the gradient, not a clip group round a rectangle, so Shape Builder, Live Paint and Pathfinder work on its outline (#1304).
     In a `.ai` opened from its editing data, a text object on a layer that shows and doesn't print stays on that layer, made from the file's text document, even where the page doesn't draw it (`crates/eps/src/import/tests_native.rs`). Such a `.ai` opens without the PDF part's warnings that text was kept as outlines when no outlined glyphs come in, and a warning counts the text objects that hold the page's type next to glyphs the page has only as outlines, which don't come in (`crates/engine/src/cmd/fileio/tests_aiimport.rs`). Where the art of a `.ai` or EPS opened from its editing data differs a little from the file's page, the warning gives the share of the page that differs away from type. When that share is 0.2% or less, the warning names the type and gives the share of the page that differs where the type is; when all the type is made from the text document, the type's share has a warning of its own beside the art's (`crates/eps/src/import/tests_native.rs`).
     PDF text opens with every glyph where the file draws it (#722): the font's kerning or none, whichever the file followed, word and character spacing, `TJ` adjustments and horizontal scaling kept per character as tracking, text rise as baseline shift within its line, vertical glyphs narrower than an em centred on their column (`/W2`, `/W`, `/DW`), justified text boxes with word spacing back as justified area type (`tests_text_placement`, fixtures written from ISO 32000-1 §9).
-    A `.ai` or PDF whose editing data holds a variable library opens with a warning that its variables and data sets weren't read, with how many of each it has, whether its layers are read or it comes in as its PDF part (`crates/engine/src/cmd/fileio/tests_aiimport.rs`).
+    A `.ai` or PDF whose editing data holds a readable variable library opens with its variable definitions, data-set rows, text, visibility and linked-file values, active row and lock in the Variables panel, whether its layers are read or it comes in as its PDF part; graph values and malformed entries are skipped with a note, and objects aren't bound yet (`crates/eps/src/import/ai/tests.rs`, `crates/engine/src/cmd/fileio/tests_aiimport.rs`).
     A `.ai` or EPS opened from its editing data keeps each artboard's center mark, cross hairs, video safe areas and video ruler pixel aspect ratio, and the file's Document Raster Effects Settings; the author comes from the header's `%%For` (the editing data's, else an EPS's own) when the file's File Info gives none, the header's custom colors that no swatch has come in as spot swatches, a named color the file defines takes the place of a default swatch of that name when the file has no palette, and an older file's `%%TemplateBox` places its artboard. A value of another type or out of range keeps its default (`crates/eps/src/import/ai/tests.rs`, `crates/eps/src/import/tests_native.rs`, `crates/engine/src/cmd/fileio/tests_aiimport.rs`).
     A `.ai` opened from its editing data opens its Objects on Path groups live, with their path, their objects in order along it, Pivot and Rotate, and their art where the file draws it; a group whose spacing has been dragged, or with options an Objects on Path group doesn't hold, opens as a plain group (`crates/eps/src/import/ai/tests.rs`).
     In a `.ai` opened from its editing data, a path or type object with Offset Path, Outline Object or Outline Stroke on the whole object opens as itself with those effects live, in their order and shown or hidden; on a fill or stroke of type they stay on that fill or stroke. Offset Path keeps its Offset, Joins and Miter Limit, and Outline Stroke takes its width from the stroke. An Offset Path with a setting missing, out of range or not read keeps the drawn art, as does a path with a Path effect on one fill or stroke (`crates/eps/src/import/ai/style/tests.rs`, `crates/eps/src/import/ai/tests.rs`, `crates/eps/src/import/tests_native.rs`).