feat(ui): align inventory + detail with mockups (seed icons, green theme)

Visual pass toward docs/mockups (06 inventory, 07 item):
- Bundle the seedks icon font (chars a–k → seed pictograms: jar, packet, spoon…)
  and a SeedGlyph/QuantityKindIcon helper.
- Green app bar + pale-green canvas theme (buildTaneTheme).
- Inventory list: rounded-square photo thumbnail or green initial avatar, bold
  title, scientific-name subtitle, trailing edit pencil, styled category
  headers, rounded search field, seed-glyph empty state.
- Quantity selectors (quick-add + add-lot) show the seed pictogram + word;
  detail lot lines use the kind's glyph.
- Detail header restyled to mockup 07: category link + scientific name on the
  left, photo on the right.

watchInventory now also returns the linked species' scientific name (subtitle).
37 app tests green; seedks font verified in the Linux asset bundle.

apps/app_seeds/lib/data/variety_repository.dart

@@ -12,6 +12,7 @@ class VarietyListItem extends Equatable {
     required this.id,
     required this.label,
     this.category,
+    this.scientificName,
     this.photo,
   });
 
@@ -19,11 +20,14 @@ class VarietyListItem extends Equatable {
   final String label;
   final String? category;
 
+  /// Scientific name of the linked species, shown as the tile subtitle.
+  final String? scientificName;
+
   /// First photo (encrypted BLOB) for the avatar, or null → show an initial.
   final Uint8List? photo;
 
   @override
-  List<Object?> get props => [id, label, category, photo];
+  List<Object?> get props => [id, label, category, scientificName, photo];
 }
 
 /// One germination test on a lot; [rate] is derived (0..1), null when it can't
@@ -154,12 +158,18 @@ class VarietyRepository {
       ]);
     return query.watch().asyncMap((rows) async {
       final photos = await _firstPhotosFor(rows.map((v) => v.id).toList());
+      final sciNames = await _scientificNamesFor(
+        rows.map((v) => v.speciesId).whereType<String>().toSet(),
+      );
       return rows
           .map(
             (v) => VarietyListItem(
               id: v.id,
               label: v.label,
               category: v.category,
+              scientificName: v.speciesId == null
+                  ? null
+                  : sciNames[v.speciesId],
               photo: photos[v.id],
             ),
           )
@@ -189,6 +199,17 @@ class VarietyRepository {
     return byVariety;
   }
 
+  /// Maps each of [speciesIds] to its scientific name (one query).
+  Future<Map<String, String>> _scientificNamesFor(
+    Set<String> speciesIds,
+  ) async {
+    if (speciesIds.isEmpty) return const {};
+    final rows = await (_db.select(
+      _db.species,
+    )..where((s) => s.id.isIn(speciesIds))).get();
+    return {for (final s in rows) s.id: s.scientificName};
+  }
+
   /// The 20-second quick-add: a [label] (required) plus an optional [category],
   /// an optional [quantity] (creates a Lot) and an optional [photoBytes]
   /// (stored as an encrypted BLOB Attachment). Returns the new Variety id.