Type: Digits — Default, Arabic, Hindi and Farsi numeral systems

Adds the Character panel menu's Digits option (with the Middle Eastern /
Indic options, beside Paragraph Direction in the Paragraph panel) as a
character attribute: CharStyle::digits, saved only when set, with
text.setFormat {digits} and text.setRangeStyle {id, start, end, digits}
("default" | "arabic" | "hindi" | "farsi"; a bad value is an error).

Shaping draws every digit of the Western, Arabic-Indic (U+0660–U+0669)
and Eastern Arabic-Indic (U+06F0–U+06F9) sets in the chosen system,
whatever was typed, before font fallback, so a font without the
Arabic-Indic digits gets a fallback for them. The text, its clusters,
the caret, selection and search stay as typed, as with All Caps; SVG
export writes the digits as drawn.

Catalog rows for Digits, Arabic, Hindi and Farsi in the ten translated
languages. Docs: docs/mcp.md (Digits), type-parity.md (digit types
done; Character Direction, kashidas, composers and the split caret
still missing), target-app-parity.md and gaps.md.

Behaviour from the public documentation (a character-level option with
the values Arabic, Hindi and Farsi in the Character panel menu):
https://helpx.adobe.com/indesign/desktop/language-and-proofing/arabic-and-hebrew/choose-digit-types.html

Tests: doc (the mapping and serialization), text (glyphs of "page 3" in
Hindi/Farsi equal the typed Arabic-Indic digits' on the typed clusters;
skips without a font covering the three sets), engine (setFormat,
setRangeStyle, undo, error), svg (digits written as drawn), ui-egui
(the menu shows with the Indic options).

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

crates/engine/src/cmd/textedit.rs

@@ -27,7 +27,7 @@ pub fn specs() -> Vec<CommandSpec> {
             "Character",
             [],
             None,
-            "{id? (default: the one selected type object), start?: byte, end?: byte (default: all text), font?, style?, size?: pt, leading?: pt|\"auto\", tracking?, kerning?: 1/1000 em|\"auto\", baselineShift?: pt, hScale?: %, vScale?: %, rotation?: deg, fill?: colour|\"none\", stroke?: colour|\"none\", strokeWidth?: pt, strokeOptions?: {weight?, cap?, join?, miterLimit?, dash?, dashOffset?, alignDashes?} (as stroke.set: the character stroke), underline?, strikethrough?, allCaps?: bool, smallCaps?: bool, position?: \"normal\"|\"superscript\"|\"subscript\" (sizes from Document Setup), features?: [\"dlig\", \"-liga\", …], charAlign?: \"romanBaseline\"|\"emBoxTop\"|\"emBoxCenter\"|\"emBoxBottom\"|\"icfTop\"|\"icfBottom\", proportionalMetrics?: bool (full-width glyphs on the font's proportional widths: `palt` in horizontal type, `vpal` in vertical type)} style a character range (size/leading/baselineShift are document points and hScale includes the object transform; runs are split at the range ends) → {id, runs}",
+            "{id? (default: the one selected type object), start?: byte, end?: byte (default: all text), font?, style?, size?: pt, leading?: pt|\"auto\", tracking?, kerning?: 1/1000 em|\"auto\", baselineShift?: pt, hScale?: %, vScale?: %, rotation?: deg, fill?: colour|\"none\", stroke?: colour|\"none\", strokeWidth?: pt, strokeOptions?: {weight?, cap?, join?, miterLimit?, dash?, dashOffset?, alignDashes?} (as stroke.set: the character stroke), underline?, strikethrough?, allCaps?: bool, smallCaps?: bool, position?: \"normal\"|\"superscript\"|\"subscript\" (sizes from Document Setup), features?: [\"dlig\", \"-liga\", …], charAlign?: \"romanBaseline\"|\"emBoxTop\"|\"emBoxCenter\"|\"emBoxBottom\"|\"icfTop\"|\"icfBottom\", proportionalMetrics?: bool (full-width glyphs on the font's proportional widths: `palt` in horizontal type, `vpal` in vertical type), digits?: \"default\"|\"arabic\"|\"hindi\"|\"farsi\" (Character panel menu › Digits: the numeral system every digit is drawn in, whatever was typed)} style a character range (size/leading/baselineShift are document points and hScale includes the object transform; runs are split at the range ends) → {id, runs}",
             has_doc,
             set_range_style
         ),
@@ -209,6 +209,20 @@ pub(crate) struct CharChange {
     small_caps: Option<Option<f64>>,
     char_align: Option<vectorcraft_doc::CharAlign>,
     proportional_metrics: Option<bool>,
+    digits: Option<vectorcraft_doc::Digits>,
+}
+
+/// `digits: "default"|"arabic"|"hindi"|"farsi"` → the numeral system the digits are drawn in.
+pub(crate) fn digits_param(p: &Value, cmd: &str) -> Result<Option<vectorcraft_doc::Digits>> {
+    use vectorcraft_doc::Digits;
+    let Some(v) = p.get("digits").filter(|v| !v.is_null()) else { return Ok(None) };
+    Ok(Some(match v.as_str() {
+        Some("default") => Digits::Default,
+        Some("arabic") => Digits::Arabic,
+        Some("hindi") => Digits::Hindi,
+        Some("farsi") => Digits::Farsi,
+        _ => return Err(bad(cmd, "`digits` must be \"default\", \"arabic\", \"hindi\" or \"farsi\"")),
+    }))
 }
 
 /// `features: ["dlig", "-liga", …]` → the canonical tag list (differences from the defaults).
@@ -293,6 +307,7 @@ impl CharChange {
             small_caps,
             char_align: char_align_param(p, cmd)?,
             proportional_metrics: flag("proportionalMetrics"),
+            digits: digits_param(p, cmd)?,
         };
         if c.size.is_some_and(|v| v <= 0.0) {
             return Err(bad(cmd, "size must be positive"));
@@ -322,6 +337,7 @@ impl CharChange {
             && self.small_caps.is_none()
             && self.char_align.is_none()
             && self.proportional_metrics.is_none()
+            && self.digits.is_none()
     }
 
     fn localize(&mut self, t: &TextObject, cmd: &str) -> Result<()> {
@@ -411,6 +427,9 @@ impl CharChange {
         if let Some(v) = self.proportional_metrics {
             st.proportional_metrics = v;
         }
+        if let Some(v) = self.digits {
+            st.digits = v;
+        }
     }
 }