i18n: Japanese has a row for every message the untranslated report lists

The Japanese catalog lacked a row for 1,842 of the status and error
messages that the untranslated report finds in the sources, so the
status bar showed those messages in English.

- ja.tsv gains 1,842 `@msg` rows: the errors of commands and their
  parameter checks, scripts, file import and export, printing and
  plug-ins. The translations are VectorCraft's own, written from the
  English meaning with the catalog's conventions and its existing
  feature names. Placeholders, parameter names, command ids and
  literal values stay as the English writes them.
- The untranslated report now lists no Japanese messages. Menu
  strings, `tl!` literals and undo labels are unchanged.
- Two of the messages have two placeholders in a row. The status bar
  cannot match such a row, so it does not use those two rows.
- The row for `{k} has control characters{_1}` does not match the
  message for a multi-line File Info field, where the last
  placeholder is empty.
- The Japanese row of docs/localization-parity.md gives the catalog's
  current message counts.

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

docs/localization-parity.md

@@ -34,7 +34,7 @@ Chinese by `imachus`). Only Georgian is recorded as reviewed by a native speaker
 | French | `fr` | 4,020 / 4,020 (100%) | all | Latin | no | full | — (review) |
 | Portuguese | `pt-br` | 6,106 catalog entries (counted 2026-10-31 on `main` at `d26dd933a`): menus, `tl!` literals and messages complete when counted; one/other plurals | all | Latin | contributor is a Brazilian Portuguese speaker; further native review welcome | full | — (review) |
 | Indonesian | `id` | 5,279 rows, 750 of them `@msg` (counted 2026-10-21): menus and `tl!` literals complete when counted; its messages are partial; one plural form | dialogs and tooltips all; 750 message rows (French has 796) | Latin | no | full | — (review) |
-| Japanese | `ja` | 4,004 / 4,020 (99.6%) | all | CJK UI font as above; Japanese IME; vertical type partial; Japanese crop marks and composition settings | no | full | — (review) |
+| Japanese | `ja` | 4,004 / 4,020 (99.6%) | all (3,459 `@msg` and 48 `@msgplural` rows, counted 2026-11-13: the untranslated report lists no missing messages for it) | CJK UI font as above; Japanese IME; vertical type partial; Japanese crop marks and composition settings | no | full | — (review) |
 | German | `de` | 3,952 / 4,020 (98%; menus, literals and messages complete when counted) | all (602 of 604 message rows; landed 2026-10-10) | Latin | contributor-written, not reviewed | full | — (review) |
 | Korean | `ko` | 4,870 rows (counted 2026-10-21): menus, `tl!` literals and messages complete when counted; one plural form | all | Hangul from an installed system font on the desktop (Apple SD Gothic Neo, Malgun Gothic, Noto Sans CJK KR…); the web build has no Korean UI font yet (craft-fonts); IME path exists | no (AI-drafted) | full | — (review; web font) |
 | Vietnamese | `vi` | 4,886 rows (counted 2026-10-21): menus, `tl!` literals and messages complete when counted; one plural form; 4,046 plain + 18 `@plural` + 28 contextual + 794 `@msg` | all | Latin with Vietnamese diacritics (stacked marks attach in precomposed, decomposed and keyboard forms, #4491; glyph tests pass) | contributor is a Vietnamese speaker; AI-assisted draft, further native review welcome | full | — (review) |

docs/target-app-parity.md

@@ -875,6 +875,7 @@ Moved from the ROADMAP's "Shipped so far" on 2026-10-10. Update it when a featur
   - The History panel, Edit › Undo and Edit › Redo translate the names of the steps that apply or redefine a character or paragraph style and of the step that redefines a graphic style: each such step keeps its template (`Apply {name}`, `Redefine {name}`, `Redefine Graphic Style “{name}”`) and the style's name, every complete catalog has a row for each template, and the panel and the menu show the style's name as the document holds it, except the Normal styles' names, which they show in the interface language (`steps_named_after_a_style_list_the_template_around_the_name`, `undo_and_redo_name_a_style_step_around_the_style_name`).
   - The status bar translates the limits a plug-in run can exceed (its instruction, time and memory budgets and its output size) and the error of a plug-in removal that leaves the plug-in's grant in the plug-in store, in every language that translates every message. The untranslated-strings report also lists messages that an error or a status takes from a `&str` constant (`plugin_limit_errors_are_translated`, `message_scan_reads_messages_held_in_constants`).
   - The status bar translates the plug-in host's other errors (manifest, module and run checks, the output an importer, exporter or effect returns, and the approval a plug-in's permissions need) in every language that translates every message. A JSON object or array inside a message stays as written, and a message that wraps another one, such as `plug-in manifest: {0}`, is matched by its own row before a row that starts with a placeholder. The reasons inside these errors (what is wrong with a parameter's spec or dialog keys, the value a parameter needs, what is wrong with an object, stroke, paint or effect in a plug-in's output) are translated with them, and the untranslated-strings report lists the reasons the plug-in host's error helpers take (`plugin_messages_are_translated_in_every_complete_catalog`, `plugin_errors_translate_with_their_values`, `plugin_error_reasons_are_translated_with_the_error`, `message_scan_reads_plugin_helpers`, `templates_that_start_with_text_match_first`).
+  - The Japanese catalog (`crates/ui-egui/src/i18n/ja.tsv`) has an `@msg` row for every status and error message the untranslated report (`untranslated_report`) finds in the sources, 3,459 `@msg` rows in all. The report's Japanese section lists no messages. The status bar does not use the rows for ``unknown parameter `{within}{key}`; {why}`` and `{name} must be {lo}–{hi}{unit} (got {v})`, because a message with two placeholders in a row cannot be matched (`Template::parse` in `crates/ui-egui/src/i18n/catalog.rs`). The row for `{k} has control characters{_1}` does not match the File Info error for a multi-line field, where the last placeholder is empty. A native speaker has not reviewed the wording.
   - The status bar translates the errors a script's `File` and `Folder` objects, `vc.run`, `$.evalFile`, the `$` object's properties and functions, `alert`, `confirm` and `prompt`, `vc.document` and `vc.log` raise, the limits a run can pass, and the errors of Drop Script Engine, and the line for a run that fails (a syntax error, a thrown error, a limit, a stop or an internal error, with the script's name, the line and column, the included file it is in and the files left written), in every language that translates every message. The script's name, paths, numbers, command ids and the text a script throws itself are shown as they are. A failure with no line and column, such as an error in code `eval` compiled, is shown with one colon after the script's name (`an_error_without_a_place_names_the_script_and_kind`). A message template that names a value twice matches only when both places hold the same text, so the line for a failed run is not taken for the message inside it (`a_repeated_placeholder_matches_the_same_text`). The untranslated-strings report also lists the messages the script host's `fail`, `value` and `over` helpers take and the errors the script interpreter throws, and a constant's text comes from the file or crate that declares it, so the Scripts menu's headers are not listed as messages (`script_errors_are_translated`, `script_host_errors_are_translated`, `message_scan_reads_script_interpreter_errors`, `message_scan_reads_constants_of_the_file_and_its_crate`, `message_scan_skips_test_modules_with_any_test_cfg`).
   - Localised UI: menus (in-window and native), panels, dialogs, toolbar and Preferences read from per-language catalogs (`crates/ui-egui/src/i18n`, see `docs/development.md`); Traditional Chinese (Taiwan), Simplified Chinese (mainland), Japanese, Korean, Vietnamese, German, Spanish, French, Italian, Polish, Brazilian Portuguese, Russian, Ukrainian, Georgian and Catalan ship complete, and Czech covers every menu label (and more), with system-locale detection on macOS, Windows, Linux and the web (the browser's languages, or `?lang=`), a Language preference and, on macOS, a VectorCraft ▸ Language menu. Names are never translated (fonts and their styles, layers, artboards, saved presets, user libraries, custom workspaces, recent files, plug-ins).
     The counts that Package's status and question, the folder search of Missing Fonts and Find Linked Files, the modified and missing linked file prompts and the CSS Properties panel's notes show use the interface language's plural forms instead of a fixed "(s)" form. Evidence: `the_missing_links_note_uses_each_count_form` in `crates/ui-egui/src/dialogs/tests_package.rs`, `the_modified_links_question_uses_each_count_form` in `crates/ui-egui/src/dialogs/missing_links.rs`, `search_counts_use_each_count_form` in `crates/ui-egui/src/dialogs/missing_fonts/tests.rs` and `the_unnamed_objects_note_uses_each_count_form` in `crates/ui-egui/src/panels/tests_css_properties.rs`.