Keep a letter and its marks in one font when falling back (#4491)

docs/localization-parity.md

@@ -1,6 +1,6 @@
 # Localization parity
 
-> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-28 · **Change:** minor (Catalan (`ca`) catalog added, complete under the tests)
+> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-29 · **Change:** minor (Vietnamese text: stacked diacritics tested and attach in every form, #4491; previously: Catalan (`ca`) catalog added, complete under the tests)
 
 Per-language status of VectorCraft's interface. How the catalogs work and how to add a language:
 [`development.md` › Localisation](development.md#localisation). Part of
@@ -37,7 +37,7 @@ Chinese by `imachus`). Only Georgian is recorded as reviewed by a native speaker
 | 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) |
 | 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 (precomposed forms; glyph tests pass) | contributor is a Vietnamese speaker; AI-assisted draft, further native review welcome | full | — (review) |
+| 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) |
 
 **12-language score: ~82%** (equal weights: 100 + 85 + 100 + 0 + 0 + 100 + 100 + 100 + 100 + 98 + 100 + 100, over 12).
 **To `full` for all twelve: ~50–85 h**, most of it Arabic (right-to-left interface) and Hindi (interface
@@ -95,6 +95,7 @@ font for the web build.
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-29 | minor | Vietnamese text: letters with two marks (Ể, Ứ, Ự) attach in precomposed, decomposed and keyboard forms, and a font lacking the marks falls back for the whole letter (#4491); scores unchanged |
 | 2026-10-28 | minor | Catalan (`ca`): complete catalog under the tests (menus, literals, messages; one/other plurals); every `ca-*` locale resolves here; AI-drafted, native review welcome. Added the Turkish and Indonesian rows the table was missing. Scores and estimates unchanged |
 | 2026-10-23 | patch | A missing translation never fails a test or a build; one untranslated report, printed by `cargo xtask ci` and `cargo xtask i18n-report`, lists the missing strings per language; scores unchanged |
 | 2026-10-16 | minor | Bulgarian (`bg`, #1909) and Greek (`el`, #2076) catalogs added, complete under the tests; Swedish (#2139) and Finnish (#1994) rows for strings added since; eighteen non-English catalogs |