feat(web): tane.comunes.org landing + localized app screenshots

- Hugo site (site/): EN/ES intro + legal (generated from docs/legal), an
  ES/EN About page from docs/{que-es-tane,what-is-tane}.md, seed-green theme,
  responsive header, store-badge placeholders, multi-stage Hugo->nginx image.
- Golden screenshot harness (test/screenshots/): en,es,fr,de,pt,ja + RTL demo,
  real fonts via DejaVu Sans + FontManifest; skip-by-default tag so CI stays
  green. collect_screenshots.sh feeds site/ and fastlane phoneScreenshots.
- Drop editorial notes from the public explainer.

apps/app_seeds/test/screenshots/screenshot_support.dart

@@ -0,0 +1,188 @@
+import 'dart:convert';
+
+import 'package:commons_core/commons_core.dart';
+import 'package:drift/drift.dart' show Value;
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart' show FontLoader, rootBundle;
+import 'package:flutter_bloc/flutter_bloc.dart';
+import 'package:flutter_localizations/flutter_localizations.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:tane/app.dart' show materialLocaleFor;
+import 'package:tane/data/species_repository.dart';
+import 'package:tane/data/variety_repository.dart';
+import 'package:tane/db/database.dart';
+import 'package:tane/db/enums.dart';
+import 'package:tane/domain/crop_calendar.dart' show monthsToMask;
+import 'package:tane/i18n/strings.g.dart';
+import 'package:tane/state/inventory_cubit.dart';
+import 'package:tane/ui/theme.dart';
+
+/// Marketing screenshot canvas: a tall phone at 3x. Logical 360x760.
+const screenshotSize = Size(1080, 2280);
+const screenshotPixelRatio = 3.0;
+
+/// Locales we render real, translated screenshots for. Asturian (`ast`) is
+/// omitted from store assets; the RTL demo is handled separately (the app has
+/// no Arabic strings yet — see [ScreenshotLocale.rtlDemo]).
+const screenshotLocales = <AppLocale>[
+  AppLocale.en,
+  AppLocale.es,
+  AppLocale.fr,
+  AppLocale.de,
+  AppLocale.pt,
+  AppLocale.ja,
+];
+
+bool _fontsLoaded = false;
+
+/// Registers real glyph-bearing fonts so golden screenshots show text and icons
+/// rather than the Ahem/tofu boxes flutter_test uses by default. Loads every
+/// family declared in the test bundle's FontManifest.json (MaterialIcons, the
+/// bundled Noto Sans JP/Arabic and seedks glyphs), then adds DejaVu Sans — a
+/// bundled asset, not a font *family* — as the Latin text face so en/es/fr/de/pt
+/// render legibly without needing Roboto.
+Future<void> loadScreenshotFonts() async {
+  if (_fontsLoaded) return;
+
+  Future<void> family(String name, List<String> assets) async {
+    final loader = FontLoader(name);
+    for (final asset in assets) {
+      loader.addFont(rootBundle.load(asset));
+    }
+    await loader.load();
+  }
+
+  final manifest =
+      json.decode(await rootBundle.loadString('FontManifest.json'))
+          as List<dynamic>;
+  for (final entry in manifest.cast<Map<String, dynamic>>()) {
+    await family(
+      entry['family'] as String,
+      [for (final f in entry['fonts'] as List) f['asset'] as String],
+    );
+  }
+
+  await family('DejaVu Sans', [
+    'assets/fonts/DejaVuSans.ttf',
+    'assets/fonts/DejaVuSans-Bold.ttf',
+  ]);
+  _fontsLoaded = true;
+}
+
+const _fontFallbacks = <String>['Noto Sans JP', 'Noto Sans Arabic'];
+
+/// The real app theme, but with every text style pinned to the bundled
+/// [DejaVu Sans] so screenshots render legible glyphs (see [loadScreenshotFonts]).
+ThemeData screenshotTheme() {
+  final base = buildTaneTheme();
+  return base.copyWith(
+    textTheme: base.textTheme.apply(
+      fontFamily: 'DejaVu Sans',
+      fontFamilyFallback: _fontFallbacks,
+    ),
+    primaryTextTheme: base.primaryTextTheme.apply(
+      fontFamily: 'DejaVu Sans',
+      fontFamilyFallback: _fontFallbacks,
+    ),
+    appBarTheme: base.appBarTheme.copyWith(
+      titleTextStyle: base.appBarTheme.titleTextStyle?.copyWith(
+        fontFamily: 'DejaVu Sans',
+        fontFamilyFallback: _fontFallbacks,
+      ),
+    ),
+  );
+}
+
+/// Wraps [child] as a full screen for capture: the real green theme with
+/// screenshot fonts, the given [locale], repositories and an [InventoryCubit].
+/// Pass [textDirection] to force RTL for the layout demo.
+Widget screenshotApp({
+  required VarietyRepository repository,
+  required SpeciesRepository species,
+  required Widget child,
+  AppLocale locale = AppLocale.en,
+  TextDirection? textDirection,
+}) {
+  LocaleSettings.setLocaleSync(locale);
+  return TranslationProvider(
+    child: MultiRepositoryProvider(
+      providers: [
+        RepositoryProvider.value(value: repository),
+        RepositoryProvider.value(value: species),
+      ],
+      child: BlocProvider(
+        create: (_) => InventoryCubit(repository),
+        child: MaterialApp(
+          debugShowCheckedModeBanner: false,
+          theme: screenshotTheme(),
+          locale: materialLocaleFor(locale.flutterLocale),
+          supportedLocales: AppLocaleUtils.supportedLocales,
+          localizationsDelegates: const [
+            GlobalMaterialLocalizations.delegate,
+            GlobalWidgetsLocalizations.delegate,
+            GlobalCupertinoLocalizations.delegate,
+          ],
+          home: textDirection == null
+              ? child
+              : Directionality(textDirection: textDirection, child: child),
+        ),
+      ),
+    ),
+  );
+}
+
+/// One seeded variety plus the id of a "hero" variety used for the detail shot.
+class SeededInventory {
+  const SeededInventory(this.heroVarietyId);
+  final String heroVarietyId;
+}
+
+/// Seeds an attractive, internationally-neutral inventory: a spread of
+/// colour-coded botanical families, lots with years/quantities/origins, photo
+/// avatars, and crop-calendar month masks so the calendar screen is populated.
+/// Returns the hero variety (a cherry tomato with several lots) for detail.
+Future<SeededInventory> seedShowcase(
+  AppDatabase db,
+  VarietyRepository repo,
+) async {
+  // Sow in spring, harvest seed in late summer — visible in the calendar.
+  final sow = monthsToMask(const [3, 4, 5]);
+  final harvest = monthsToMask(const [8, 9]);
+
+  // Varieties render with the app's default coloured-initial disc avatar —
+  // the on-brand default when no photo is set — so no image decoding is needed.
+  Future<String> add(String label, String family) async {
+    final id = await repo.addQuickVariety(label: label, category: family);
+    await (db.update(db.varieties)..where((v) => v.id.equals(id))).write(
+      VarietiesCompanion(
+        sowMonths: Value(sow),
+        seedHarvestMonths: Value(harvest),
+      ),
+    );
+    return id;
+  }
+
+  final tomato = await add('Cherry tomato', 'Solanaceae');
+  await repo.addLot(
+    varietyId: tomato,
+    harvestYear: 2024,
+    quantity: const Quantity(kind: QuantityKind.handful),
+    originName: 'Community seed swap',
+    abundance: Abundance.plentyToShare,
+    offerStatus: OfferStatus.shared,
+  );
+  await repo.addLot(
+    varietyId: tomato,
+    harvestYear: 2023,
+    quantity: const Quantity(kind: QuantityKind.packet, count: 1),
+    offerStatus: OfferStatus.exchange,
+  );
+
+  await add('Climbing bean', 'Fabaceae');
+  await add('Sunflower', 'Asteraceae');
+  await add('Sweet basil', 'Lamiaceae');
+  await add('Rainbow chard', 'Amaranthaceae');
+  await add('Purple carrot', 'Apiaceae');
+
+  return SeededInventory(tomato);
+}