Accent-insensitive card search

A fold() (lowercase + strip accents, using the same table as nucleo's own
normalization) is registered as a SQLite function and used by the name,
oracle-text and location filters, so "khazad-dum" finds Troll of
Khazad-dûm. The fuzzy name search folds the query too (accented queries
used to match nothing) and its exact-name promotion; decklist/ManaBox
import falls back to a folded name match; the deck quick filter and tag
suggestions fold client-side.

Closes #17

src/components.tsx

@@ -632,6 +632,12 @@ export const CardSearchBox = forwardRef<
   );
 });
 
+/** Lowercase and strip accents, so "khazad-dum" matches "Khazad-dûm". The
+ *  frontend twin of `mtgc_core::text::fold`, for matching done client-side. */
+export function fold(s: string): string {
+  return s.normalize("NFD").replace(/\p{M}/gu, "").toLowerCase();
+}
+
 /**
  * A chip-based multi-value text filter with autocomplete: selected values
  * render as removable chips, and typing filters `suggestions` into a
@@ -653,11 +659,11 @@ export function TagInput({
   const [text, setText] = useState("");
   const [sel, setSel] = useState(0);
 
-  const query = text.trim().toLowerCase();
+  const query = fold(text.trim());
   const filtered = query
     ? suggestions
         .filter((s) => !values.some((v) => v.toLowerCase() === s.toLowerCase()))
-        .filter((s) => s.toLowerCase().includes(query))
+        .filter((s) => fold(s).includes(query))
         .slice(0, 8)
     : [];
 

src/views/DeckView.tsx

@@ -37,6 +37,7 @@ import {
   usePersistedState,
   useTileColumns,
   useViewMode,
+  fold,
 } from "../components";
 import { SuggestionsModal } from "../SuggestionsModal";
 import { useBackButton } from "../backButton";
@@ -878,9 +879,9 @@ export function DeckView({ refreshSignal }: { refreshSignal?: number }) {
   // filter only, distinct from the CardSearchBox boxes below (which search
   // the library/reference db to find NEW cards to add).
   function matchesFilter(e: DeckEntry): boolean {
-    const q = filterQuery.trim().toLowerCase();
+    const q = fold(filterQuery.trim());
     if (!q) return true;
-    return e.name.toLowerCase().includes(q) || e.type_line.toLowerCase().includes(q);
+    return fold(e.name).includes(q) || fold(e.type_line).includes(q);
   }
 
   const owned = contents.filter((e) => !e.is_maybeboard && e.quantity_owned > 0 && matchesFilter(e));