EPS import: a PostScript error shows what its name means in the interface language

An EPS or PostScript file that stops on a PostScript error named the
error, such as typecheck or rangecheck, with the operator and the
procedure, but did not say what the name means in any language.

The warning or error now gives the name as PostScript spells it,
followed by VectorCraft's own wording of what it means in the reader:
"a PostScript error (typecheck in `add`; a value has the wrong type for
the operator)". vectorcraft_eps::POSTSCRIPT_ERRORS lists the 14 names
the reader raises other than undefined, with their meanings, and a
test checks that each of those names has one. Each meaning and the
new message shapes have a row in every catalog. i18n::message now
translates placeholder values five levels deep instead of three, which
the status bar's line for an EPS file that can't be opened needs.

Docs: docs/mcp.md, docs/target-app-parity.md.

docs/mcp.md

@@ -3519,7 +3519,9 @@ point type in the font the file names (embedded font programs are skipped). In a
 (else `%%BoundingBox`; a letter page without one). A program the interpreter can't run (an operator it doesn't know,
 an error, a runaway loop) or that draws nothing comes in as its TIFF preview (palette previews with an alpha channel
 too) with a warning; without a preview, the art drawn up to the error is kept with a warning, and a file with none is
-refused with a message saying why.
+refused with a message saying why. A PostScript error is named as PostScript spells it, followed by what it means:
+``a PostScript error (typecheck in `add`; a value has the wrong type for the operator)``. The status bar shows
+the meaning in the interface language, and the name stays as it is.
 
 ```json
 {"name":"run_command","arguments":{"command":"document.open","params":{"path":"/tmp/logo.eps"}}}

docs/target-app-parity.md

@@ -490,6 +490,7 @@ Moved from the ROADMAP's "Shipped so far" on 2026-10-10. Update it when a featur
   - Native macOS menu bar, vector tool cursors, a ⌘K command palette, middle-button panning with any tool. Native menus explicitly end tracking on command selection, outside window presses and Escape; menu updates wait until tracking ends, and a dismissing press never starts a canvas gesture (M14.8).
   - The errors of the blend spine commands (Move Spine Point, Reshape Spine Segment, Add Spine Point and Delete Spine Point) show in the status bar in the interface language: each has a row in every catalog that translates all status and error messages and in Bulgarian (`blend_spine_param_errors_are_translated`).
   - The errors of the parameter checks that many commands share show in the status bar in the interface language: a value that is not a number where a number goes (`object.move` with `"dx": "60 mm"`, and `object.rotate`, `object.setBounds` and the other commands that call `check_numbers`), a missing number or index, `ids` that are not a list of object ids, an object id that is not a non-negative integer or names no object, and a date that is not Unix seconds. Each has a row in every catalog that translates all status and error messages, and in Bulgarian, Danish, Indonesian and Dutch (`shared_param_check_errors_are_translated`).
+  - An EPS or PostScript file that stops on a PostScript error gives the error's name as PostScript spells it (`typecheck`, `rangecheck` and the other names the reader raises, except `undefined`, whose message names the unknown name) followed by what it means, in the warning after opening and in the error when the file can't be opened. The status bar and the open-error dialog show the meaning in the interface language: each meaning has a row in every catalog (`postscript_error_meanings_are_translated`).
   - The macOS menu bar is built from the in-window menus (one model, `native_menu`) and laid out as a Mac app's: the VectorCraft menu holds About, Settings ▸ (each Preferences page, General… ⌘K), Language ▸, Appearance ▸ (UI brightness), Services, Hide VectorCraft ⌃⌘H (⌘H stays Hide Edges), Hide Others, Show All and Quit; Window gains Minimize ⌃⌘M, Zoom and Bring All to Front, and Help the system's search field. Its key equivalents go back to egui as key presses, so user shortcuts, focused text fields and the Type tool's input method behave as in the window, and nothing fires twice; enabled, check marks and labels update in place. `--in-window-menus` or `VECTORCRAFT_IN_WINDOW_MENUS=1` keeps the menus in the window; `ui.inspect` reports `nativeMenuBar`.
   - macOS: Finder opens every format File › Open reads with VectorCraft (double-click, Open With, a drop on the Dock icon, `open -a`), at launch or while it runs; the release and `cargo xtask bundle` apps share one `Info.plist` that declares those document types, owning only VectorCraft's own formats. The DMG opens on a designed Finder window, VectorCraft.app beside the `Applications` link over a background with the app icon (#493).
   - Swatch and graphic style libraries, Libraries panel files, presets and plug-ins open wherever they are dropped on the window, as File › Open opens them.