feat(inventory): photo-first drafts + on-device OCR (digitization R2+R4)

Lower the bulk-digitization cliff with two more routes on top of the
already-landed CSV import and "save and add another":

- Photo-first drafts (capture now, catalogue later): burst-capture
  photos (camera or multi-gallery) into unnamed draft varieties, shown
  in a "to catalogue" tray, hidden from the main list until named.
  Adds Variety.isDraft (schema), addDraftVariety/watchDrafts/nameDraft,
  the triage sheet and the inventory banner.
- On-device OCR label suggestion (Tesseract, offline, no Google): a
  "Suggest name from photo" button in the naming dialog behind a
  LabelTextExtractor interface (Tesseract on Android/iOS, no-op
  elsewhere). Reads the largest print via hOCR bounding boxes, drops
  boilerplate/low-confidence noise, preprocesses (grayscale, contrast,
  upscale) and sweeps rotations (0-315 deg) so tilted packets still
  read. Bundles tessdata_fast eng+spa; validated on-device against real
  packets. The photo is written to a temp file deleted immediately in a
  finally block (the plugin needs a path) - a bounded, documented
  exception to no-plaintext-at-rest.

This commit also carries the co-developed schema evolution v5 to v8 that
shares these files (organic flag, species viability years, crop
calendar, lot provenance/abundance/preservation format, condition
checks) plus their exports/migrations and i18n.

Tests: CSV/draft/OCR unit + widget + migration green in isolation.
Note: the full widget suite currently hangs (>10 min) - under investigation.

apps/app_seeds/lib/main.dart

@@ -5,16 +5,20 @@ import 'data/species_repository.dart';
 import 'data/variety_repository.dart';
 import 'di/injector.dart';
 import 'i18n/strings.g.dart';
+import 'services/onboarding_store.dart';
 
 Future<void> main() async {
   WidgetsFlutterBinding.ensureInitialized();
   LocaleSettings.useDeviceLocaleSync();
   await configureDependencies();
+  final onboarding = getIt<OnboardingStore>();
   runApp(
     TranslationProvider(
       child: TaneApp(
         repository: getIt<VarietyRepository>(),
         species: getIt<SpeciesRepository>(),
+        onboarding: onboarding,
+        showIntro: !await onboarding.introSeen(),
       ),
     ),
   );