i18n: Simplified Chinese translates status-bar and error messages

The Simplified Chinese catalog had 20 `@msg` rows, against 714 to 718
in each catalog listed in COMPLETE_MESSAGES, so with the interface in
Simplified Chinese most status-bar and error messages showed in
English.

- zh-hans.tsv gains the 694 missing `@msg` rows in one block with a
  header comment on its conventions: no final 。 unless the English
  ends with a period, a space between Chinese and adjacent Latin
  text, numbers or placeholders, and 、 between list items. The rows
  use the catalog's existing terms (画板, 图稿, 编组, 描边, 色板, 实时上色,
  图像描摹, 增效工具 ...).
- zh-hans joins COMPLETE_MESSAGES, so
  complete_languages_translate_every_message and the narrower message
  tests fail when a zh-hans message row is missing, and a new message
  needs a zh-hans row.
- The registry comment, docs/development.md (which also gains Greek,
  already in COMPLETE_MESSAGES), the zh-hans row of
  docs/localization-parity.md, and the interface-languages line of
  docs/target-app-parity.md (which also gains Czech, Greek, Hungarian,
  Swedish and Finnish) list Simplified Chinese among the languages
  that translate messages.

docs/development.md

@@ -233,7 +233,7 @@ other `sv-*` locale resolve to it), Czech (`cs`, every menu label) and Brazilian
   control channel, MCP and tests read them) and are translated only where the status bar draws them
   (`i18n::msg`). `@msg` catalog rows hold a whole message or a template such as
   `Couldn't open {name}: {e}`; `{_1}`, `{_2}` … stand for the format string's `{}`, and the values in the
-  placeholders are translated in turn (the reason after `: {e}` is often a message too). Czech, German, Spanish, French, Hungarian, Italian, Japanese, Korean, Polish, Brazilian Portuguese, Russian, Swedish, Ukrainian, Vietnamese and Finnish cover every
+  placeholders are translated in turn (the reason after `: {e}` is often a message too). Czech, German, Greek, Spanish, French, Hungarian, Italian, Japanese, Korean, Polish, Brazilian Portuguese, Russian, Simplified Chinese, Swedish, Ukrainian, Vietnamese and Finnish cover every
   message literal the test scan finds (`complete_languages_translate_every_message`, languages listed in
   `COMPLETE_MESSAGES`): a new `Err("…")`, `Other(…)`, `#[error(…)]` or `status(…)` message needs a row in each of those catalogs (`VECTORCRAFT_I18N_DUMP_MESSAGES=messages.txt cargo test -p vectorcraft-ui-egui
   complete_languages_translate_every_message` lists them all). Other languages show messages in English

docs/localization-parity.md

@@ -24,7 +24,7 @@ Chinese by `imachus`). None is recorded as reviewed by a native speaker; the cat
 | Language | Code | UI strings translated | Dialogs / tooltips / messages | Script support | Native review | Status | To `full` (h) |
 |---|---|---|---|---|---|---|---|
 | English | `en` | source, 100% | all | Latin | — | full | — |
-| Simplified Chinese (Mandarin) | `zh-hans` | 3,647 rows; menus, panels, dialogs complete (tests); 85% overall | messages in English (1 of 604) | CJK UI font from craft-fonts (BIZ UDPGothic) when embedded, else a system font; IME with marked text at the caret; vertical type partial ([type-parity.md](type-parity.md)) | no | partial | 2–3 |
+| Simplified Chinese (Mandarin) | `zh-hans` | 4,761 rows, 714 of them `@msg` (counted 2026-10-16): menus, `tl!` literals and messages complete (tests) | all | CJK UI font from craft-fonts (BIZ UDPGothic) when embedded, else a system font; IME with marked text at the caret; vertical type partial ([type-parity.md](type-parity.md)) | no | full | — (review) |
 | Spanish | `es` | 4,009 / 4,020 (99.7%) | all (604 messages) | Latin | no | full | — (review) |
 | Hindi | `hi` | 0 | none | Devanagari: the document's text shapes (HarfRust), with tests of conjuncts, reph, pre-base matras, nukta forms and caret stops that run when an OpenType Devanagari font is installed, but the egui interface does no complex shaping | no | none | 20–30 |
 | Arabic | `ar` | 0 | none | document text: bidi layout and Paragraph Direction; interface: no right-to-left layout, no Arabic shaping in egui | no | none | 25–40 |

docs/target-app-parity.md

@@ -565,7 +565,7 @@ Moved from the ROADMAP's "Shipped so far" on 2026-10-10. Update it when a featur
   For Auto Size area type in columns, the bisection for the frame's height runs on the lines of the one-column layout, and its result is checked with at most two layouts of the columns. When the text wraps around objects or does not fit the one-column layout, or when the check fails, the columns are laid out at every step of the bisection, as before. Typing at the start of a story of 50,000 characters in 2 columns took 1,670 ms a keystroke and now takes 292 ms (release build, `auto_height_in_columns_typing_timing`).
   An edit copies a thread's story only when it changes one of the thread's frames: with a story of 50,000 characters threaded through 8 frames with a style change at every word, moving another object took 7.8 ms and now takes 0.013 ms, and a frame of a drag took 7.2 ms and now takes 0.012 ms (release build, `threaded_story_edit_timing`).
   The Paragraph panel menu's Hyphenation… (`ui.hyphenation`, `text.setFormat {wordsLongerThan, afterFirst, beforeLast, hyphenLimit, hyphenationZone, hyphenateCapitalized}`) sets each paragraph's hyphenation limits: the shortest word that breaks, the fewest letters on each side of the hyphen, the most hyphenated lines in a row, a zone at the right edge where the Single-line Composer breaks before a word instead of hyphenating it, and whether capitalized words break. The defaults are words longer than 5 letters, 3 letters on each side, no limit or zone, and capitalized words hyphenated; paragraph styles and the native file keep the options.
-- **Interface languages, vertical type:** Preferences ▸ User Interface (or VectorCraft ▸ Language on macOS) picks Automatic (the system locale) or a registered language, persisted as `interfaceLanguage`. Translations come from per-language catalogs (`i18n/*.tsv`): Traditional and Simplified Chinese, Japanese, German (every `de-*` locale), Spanish (neutral international Spanish, for every `es-*` locale), French (every `fr-*` locale), Italian (every `it-*` locale) Russian (every `ru-*` locale) and Ukrainian (every `uk-*` locale) cover the whole interface, Czech every menu label; German, Spanish, French, Italian, Japanese, Korean, Vietnamese, Polish, Brazilian Portuguese, Russian and Ukrainian also translate status-bar and error messages as they are shown (`@msg` templates, every message literal tested; the messages themselves stay English for agents); untranslated text stays English. Japanese and Chinese glyphs come from the craft-fonts build input (release builds) or the installed fonts, Czech, German, Spanish, French, Italian, Russian and Ukrainian ones from the bundled UI fonts. The web app follows the browser's languages (or `?lang=`). The Basic toolbar's Type button holds Vertical Type in its flyout. Vertical Type, Vertical Area Type and Vertical Type on a Path create vertical text (columns right to left, upright CJK glyphs and marks with `vert` alternates, Latin and longer numbers on their side, two- and three-digit numbers set as tate-chu-yoko in one em of the column (kept whole when justified), upright glyphs centred on the column (tracked or justified too), point type's anchor on the first column's centre line); kinsoku applies to horizontal and vertical Japanese (Paragraph panel › Kinsoku Set, `text.setFormat {kinsoku}`: Hard, the default, keeps closing marks, iteration marks, the prolonged sound mark and small kana off the line start and opening brackets off its end; Soft lets 々, ー and small kana start a line as JLREQ's level 3 rules do; None turns it off), and justified Japanese lines spread their room between characters (not inside Latin words); Paragraph panel › Mojikumi Set (shown with Preferences › Type › Show East Asian Options, `text.setFormat {mojikumi}`): None or Line-end Punctuation Half Width (new type's default, as in Illustrator; older documents and imported text keep None) shares one half-em space between consecutive punctuation, sets a closing mark ending a line half width and an opening bracket starting a line flush with its start (a paragraph's first line at its first-line indent, JIS X 4051's principle in JLREQ 3.1.5), and puts a quarter em between Japanese and Latin letters or digits; Paragraph panel menu › Top-to-Top / Bottom-to-Bottom Leading measures leading from em box top to top (area type's first line touches the frame) or from baseline to baseline (new type in a Japanese interface starts top to top, with em box centre character alignment, #432); Paragraph panel menu › Burasagari None / Regular / Force (`text.setFormat {burasagari: "none"|"standard"|"forced"}`) hangs an East Asian comma or full stop (、。，．､｡) ending an area type line outside it, Regular (new type's default) when it doesn't fit and Force always (the rest of the line then fills the measure; closing brackets and Latin punctuation don't hang); Character panel menu › Character Alignment (with the East Asian options; `text.setFormat` or `text.setRangeStyle {charAlign}`) lines characters smaller than the largest on their line up on the Roman baseline, the em box top/right, centre or bottom/left, or the ICF (ideographic character face) top/right or bottom/left, from the font's BASE table or, without one, the average ink box of some ideographs and kana; Proportional Metrics (the same menu; `{proportionalMetrics}`) sets full-width glyphs on the font's proportional widths (OpenType `palt`) in horizontal type and upright glyphs on its proportional heights (`vpal`, shaped top to bottom; fonts without vertical metrics keep their cells) in vertical type, and Line-end Punctuation Half Width takes nothing more off the punctuation they re-spaced; Type ▸ Type Orientation switches existing text; caret, selection, hit testing and arrow keys follow the writing direction. Vertical text exports to PDF as real text and to SVG as outlines. The interface is available in Polish (`pl`): menus, panels, dialogs and messages, with one/few/many plurals; AI-drafted, native review pending (#1498).
+- **Interface languages, vertical type:** Preferences ▸ User Interface (or VectorCraft ▸ Language on macOS) picks Automatic (the system locale) or a registered language, persisted as `interfaceLanguage`. Translations come from per-language catalogs (`i18n/*.tsv`): Traditional and Simplified Chinese, Japanese, German (every `de-*` locale), Spanish (neutral international Spanish, for every `es-*` locale), French (every `fr-*` locale), Italian (every `it-*` locale) Russian (every `ru-*` locale) and Ukrainian (every `uk-*` locale) cover the whole interface, Czech every menu label; Czech, German, Greek, Spanish, French, Hungarian, Italian, Japanese, Korean, Vietnamese, Polish, Brazilian Portuguese, Russian, Simplified Chinese, Swedish, Ukrainian and Finnish also translate status-bar and error messages as they are shown (`@msg` templates, every message literal tested; the messages themselves stay English for agents); untranslated text stays English. Japanese and Chinese glyphs come from the craft-fonts build input (release builds) or the installed fonts, Czech, German, Spanish, French, Italian, Russian and Ukrainian ones from the bundled UI fonts. The web app follows the browser's languages (or `?lang=`). The Basic toolbar's Type button holds Vertical Type in its flyout. Vertical Type, Vertical Area Type and Vertical Type on a Path create vertical text (columns right to left, upright CJK glyphs and marks with `vert` alternates, Latin and longer numbers on their side, two- and three-digit numbers set as tate-chu-yoko in one em of the column (kept whole when justified), upright glyphs centred on the column (tracked or justified too), point type's anchor on the first column's centre line); kinsoku applies to horizontal and vertical Japanese (Paragraph panel › Kinsoku Set, `text.setFormat {kinsoku}`: Hard, the default, keeps closing marks, iteration marks, the prolonged sound mark and small kana off the line start and opening brackets off its end; Soft lets 々, ー and small kana start a line as JLREQ's level 3 rules do; None turns it off), and justified Japanese lines spread their room between characters (not inside Latin words); Paragraph panel › Mojikumi Set (shown with Preferences › Type › Show East Asian Options, `text.setFormat {mojikumi}`): None or Line-end Punctuation Half Width (new type's default, as in Illustrator; older documents and imported text keep None) shares one half-em space between consecutive punctuation, sets a closing mark ending a line half width and an opening bracket starting a line flush with its start (a paragraph's first line at its first-line indent, JIS X 4051's principle in JLREQ 3.1.5), and puts a quarter em between Japanese and Latin letters or digits; Paragraph panel menu › Top-to-Top / Bottom-to-Bottom Leading measures leading from em box top to top (area type's first line touches the frame) or from baseline to baseline (new type in a Japanese interface starts top to top, with em box centre character alignment, #432); Paragraph panel menu › Burasagari None / Regular / Force (`text.setFormat {burasagari: "none"|"standard"|"forced"}`) hangs an East Asian comma or full stop (、。，．､｡) ending an area type line outside it, Regular (new type's default) when it doesn't fit and Force always (the rest of the line then fills the measure; closing brackets and Latin punctuation don't hang); Character panel menu › Character Alignment (with the East Asian options; `text.setFormat` or `text.setRangeStyle {charAlign}`) lines characters smaller than the largest on their line up on the Roman baseline, the em box top/right, centre or bottom/left, or the ICF (ideographic character face) top/right or bottom/left, from the font's BASE table or, without one, the average ink box of some ideographs and kana; Proportional Metrics (the same menu; `{proportionalMetrics}`) sets full-width glyphs on the font's proportional widths (OpenType `palt`) in horizontal type and upright glyphs on its proportional heights (`vpal`, shaped top to bottom; fonts without vertical metrics keep their cells) in vertical type, and Line-end Punctuation Half Width takes nothing more off the punctuation they re-spaced; Type ▸ Type Orientation switches existing text; caret, selection, hit testing and arrow keys follow the writing direction. Vertical text exports to PDF as real text and to SVG as outlines. The interface is available in Polish (`pl`): menus, panels, dialogs and messages, with one/few/many plurals; AI-drafted, native review pending (#1498).
 - **Transparency:** opacity masks (clip/invert/disable/link), exported as SVG `<mask>` and PDF soft masks. The constant alpha soft mask that PDF and `.ai` export draw a CMYK page with transparency through is white, so applications that read every soft mask by its luminosity show the page too (#1359, part of #1286).
   Disable, Enable, Unlink and Link Opacity Mask and Opacity Mask Options (`transparency.setOpacityMask`) record no undo step when every mask they act on already has the flags they set.
 - **Image Trace, thin closed outlines:** generated `fit::snap_area_tests` verify nonzero interiors after straightening, opposite closed-boundary winding and Noise controls; see [quality notes](image-trace-quality.md#thin-closed-outlines-with-snap-curves-to-lines). Scores and hours unchanged; open-piece fitting is unchanged.