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/test/services/ocr/ocr_language_test.dart

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+import 'package:flutter_test/flutter_test.dart';
+import 'package:tane/services/ocr/ocr_language.dart';
+
+void main() {
+  group('parseAvailableOcrLanguages', () {
+    test('strips the .traineddata suffix', () {
+      final available = parseAvailableOcrLanguages(
+        '{"files": ["eng.traineddata", "spa.traineddata"]}',
+      );
+      expect(available, {'eng', 'spa'});
+    });
+
+    test('empty / missing files yields empty set', () {
+      expect(parseAvailableOcrLanguages('{}'), isEmpty);
+      expect(parseAvailableOcrLanguages('{"files": []}'), isEmpty);
+    });
+  });
+
+  group('tesseractCodeForLocale', () {
+    test('maps ISO 639-1 to Tesseract codes', () {
+      expect(tesseractCodeForLocale('es'), 'spa');
+      expect(tesseractCodeForLocale('en'), 'eng');
+      expect(tesseractCodeForLocale('ar'), 'ara');
+      expect(tesseractCodeForLocale('zh'), 'chi_sim');
+    });
+
+    test('accepts full locale tags and is case-insensitive', () {
+      expect(tesseractCodeForLocale('es_ES'), 'spa');
+      expect(tesseractCodeForLocale('zh-Hans-CN'), 'chi_sim');
+      expect(tesseractCodeForLocale('DE'), 'deu');
+    });
+
+    test('unmapped locale returns null', () {
+      expect(tesseractCodeForLocale('xx'), isNull);
+    });
+  });
+
+  group('resolveOcrLanguages', () {
+    const bundled = {'eng', 'spa'};
+
+    test('preferred locale comes first, baseline appended', () {
+      expect(
+        resolveOcrLanguages(preferredLocales: ['es'], available: bundled),
+        'spa+eng',
+      );
+    });
+
+    test('English preferred is not duplicated by the baseline', () {
+      expect(
+        resolveOcrLanguages(preferredLocales: ['en'], available: bundled),
+        'eng',
+      );
+    });
+
+    test('order follows preference, de-duplicated', () {
+      expect(
+        resolveOcrLanguages(
+          preferredLocales: ['es', 'en', 'es'],
+          available: bundled,
+        ),
+        'spa+eng',
+      );
+    });
+
+    test('unbundled locale falls back to the Latin baseline', () {
+      // German pack is not bundled here — degrade to eng, never fail.
+      expect(
+        resolveOcrLanguages(preferredLocales: ['de'], available: bundled),
+        'eng',
+      );
+    });
+
+    test('a future RTL/CJK pack lights up automatically once bundled', () {
+      expect(
+        resolveOcrLanguages(
+          preferredLocales: ['ar'],
+          available: {'eng', 'spa', 'ara'},
+        ),
+        'ara+eng',
+      );
+    });
+
+    test('no baseline available: falls back to every bundled pack, sorted', () {
+      expect(
+        resolveOcrLanguages(
+          preferredLocales: ['fr'],
+          available: {'spa', 'deu'},
+        ),
+        'deu+spa',
+      );
+    });
+
+    test('empty available yields empty string', () {
+      expect(
+        resolveOcrLanguages(preferredLocales: ['es'], available: const {}),
+        '',
+      );
+    });
+  });
+}

apps/app_seeds/test/services/ocr/tesseract_label_extractor_test.dart

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+import 'package:flutter_test/flutter_test.dart';
+import 'package:tane/services/ocr/tesseract_label_extractor.dart';
+
+/// Builds one hOCR word span with a bounding box (height = y1 - y0) and an
+/// optional recognition confidence.
+String word(String text, int x0, int y0, int x1, int y1, {int conf = 90}) =>
+    "<span class='ocrx_word' title='bbox $x0 $y0 $x1 $y1; x_wconf $conf'>"
+    '$text</span>';
+
+String page(List<String> words) =>
+    "<div class='ocr_page'>${words.join('\n')}</div>";
+
+void main() {
+  group('pickLabelFromHocr picks the largest print, not the longest line', () {
+    test('Aubergine Black Beauty packet → the variety name, not boilerplate', () {
+      // "Organic Product" (14 letters) is longer than "Black Beauty" (11) but
+      // printed smaller — the old longest-line heuristic wrongly picked it.
+      final hocr = page([
+        word('BonPrime', 120, 300, 300, 335), // brand, tiny
+        word('Organic', 130, 1050, 320, 1095), // boilerplate, small
+        word('Product', 130, 1100, 340, 1145),
+        word('AUBERGINE', 380, 1180, 900, 1300), // the title (tallest)
+        word('BLACK', 380, 1330, 620, 1410),
+        word('BEAUTY', 640, 1330, 900, 1410),
+        word('HERB', 430, 1470, 560, 1510), // boilerplate, small
+        word('SEEDS', 580, 1470, 740, 1510),
+      ]);
+      expect(pickLabelFromHocr(hocr), 'Aubergine Black Beauty');
+    });
+
+    test('Cucumber Supermarketer packet → the variety name', () {
+      final hocr = page([
+        word('BonPrime', 120, 300, 300, 335),
+        word('Organic', 130, 1050, 320, 1095),
+        word('Product', 130, 1100, 340, 1145),
+        word('CUCUMBER', 300, 1200, 820, 1320), // tallest
+        word('SUPERMARKETER', 320, 1350, 900, 1430),
+        word('HERB', 430, 1470, 560, 1510),
+        word('SEEDS', 580, 1470, 740, 1510),
+      ]);
+      expect(pickLabelFromHocr(hocr), 'Cucumber Supermarketer');
+    });
+
+    test('reads left-to-right within the same row', () {
+      final hocr = page([
+        word('CHERRY', 400, 1000, 560, 1090),
+        word('TOMATO', 580, 1000, 760, 1090),
+      ]);
+      expect(pickLabelFromHocr(hocr), 'Cherry Tomato');
+    });
+
+    test('a page of only boilerplate yields null', () {
+      final hocr = page([
+        word('Organic', 130, 1050, 320, 1095),
+        word('Product', 130, 1100, 340, 1145),
+        word('HERB', 430, 1470, 560, 1510),
+        word('SEEDS', 580, 1470, 740, 1510),
+      ]);
+      expect(pickLabelFromHocr(hocr), isNull);
+    });
+
+    test('empty hOCR yields null', () {
+      expect(pickLabelFromHocr(page(const [])), isNull);
+      expect(pickLabelFromHocr(''), isNull);
+    });
+
+    test('short OCR fragments ("Re Ma") are dropped → no suggestion', () {
+      // Blurry misread into 1–2 char blobs: better nothing than "Re Ma".
+      final hocr = page([
+        word('Re', 300, 1200, 420, 1320, conf: 40),
+        word('Ma', 460, 1200, 600, 1320, conf: 40),
+      ]);
+      expect(pickLabelFromHocr(hocr), isNull);
+    });
+
+    test('a plausibly-misread title word is kept (user edits it)', () {
+      // "Sucumber" (C read as S) is useful as an editable prefill.
+      final hocr = page([
+        word('Sucumber', 300, 1200, 820, 1320, conf: 45),
+        word('Organic', 130, 1050, 320, 1095, conf: 80),
+      ]);
+      expect(pickLabelFromHocr(hocr), 'Sucumber');
+    });
+
+    test('a near-zero confidence word is dropped by the floor', () {
+      final hocr = page([word('Xzqwp', 300, 1200, 820, 1320, conf: 8)]);
+      expect(pickLabelFromHocr(hocr), isNull);
+    });
+  });
+}