feat(species): auto-classify variety species from its label

Infer the catalog species a free-text variety label names ("Maiz de la
abuela" -> Zea mays) and prefill the category from the species family.

- Pure, testable matcher (domain/species_autoclassify.dart): whole-word,
  accent/case-insensitive, Unicode-aware (any script), longest-name-wins,
  ambiguous names left unclassified, light plural fold.
- Quick-add and draft naming auto-link the species when the field is empty
  (non-destructive; an explicit category is kept).
- Edit sheet offers a one-tap suggestion from the typed name.

Tests: matcher unit, repository integration, SpeciesRepository.classifyLabel,
and an edit-sheet widget test.

apps/app_seeds/test/data/species_repository_test.dart

@@ -224,4 +224,17 @@ void main() {
     final results = await repo.search('Genus', limit: 5);
     expect(results.length, 5);
   });
+
+  test('classifyLabel infers the species named in a free-text label', () async {
+    await repo.seedBundled(_seeds);
+
+    final match = await repo.classifyLabel('Tomate cherry', languageCode: 'es');
+    expect(match, isNotNull);
+    expect(match!.scientificName, 'Solanum lycopersicum');
+    expect(match.family, 'Solanaceae');
+    expect(match.commonName, 'Tomate'); // best name for the locale
+
+    // No species named → no suggestion.
+    expect(await repo.classifyLabel('Girasol gigante'), isNull);
+  });
 }