feat(i18n): complete Portuguese, add Brazilian Portuguese (pt_BR)

Fill the ~74 UI strings pt.i18n.json was missing (saved searches, label
scanning, Plantaré, lot history), then add pt_BR as a proper Brazilian
variant rather than a copy of European Portuguese: tu/teu/tua -> você/
seu/sua with matching verb conjugation, partilhar -> compartilhar, and
Guardar -> Salvar for UI actions (seed-saving keeps "guardar", the
correct term in both variants). Wires AppLocale.ptBr into the language
picker and regenerates slang output.

apps/app_seeds/lib/i18n/ja.i18n.json

@@ -1,46 +1,47 @@
 {
-    "app": {
-        "title": "Tane"
-    },
-    "common": {
-        "save": "保存",
-        "cancel": "キャンセル",
-        "delete": "削除",
-        "edit": "編集",
-        "type": "種類",
-        "comingSoon": "近日公開",
-        "offline": "オフラインです — 共有を一時停止しています"
-    },
-    "menu": {
-        "tagline": "あなたの種子バンク",
-        "inventory": "在庫",
-        "market": "マーケット",
-        "profile": "プロフィール",
-        "chat": "チャット",
-        "wishlist": "お気に入り",
-        "following": "フォロー中",
-        "calendar": "カレンダー",
-        "settings": "設定"
-    },
-    "settings": {
-        "language": "言語",
-        "systemLanguage": "システムの言語",
-        "langEs": "Español",
-        "langEn": "English",
-        "langPt": "Português",
-        "langAst": "Asturianu",
-        "langFr": "Français",
-        "langDe": "Deutsch",
-        "langJa": "日本語",
-        "about": "このアプリについて",
-        "aboutText": "在来種のためのローカルファースト・暗号化在庫管理。AGPL-3.0。",
-        "aboutOpen": "Tane について"
-    },
-    "home": {
-        "tagline": "地域の種を分かち合い、育てよう",
-        "openMarket": "マーケット",
-        "openMarketSubtitle": "近くの種を見つけて分かち合う",
-        "yourInventory": "あなたの在庫",
-        "yourInventorySubtitle": "種を管理する"
-    }
+  "app": {
+    "title": "Tane"
+  },
+  "common": {
+    "save": "保存",
+    "cancel": "キャンセル",
+    "delete": "削除",
+    "edit": "編集",
+    "type": "種類",
+    "comingSoon": "近日公開",
+    "offline": "オフラインです — 共有を一時停止しています"
+  },
+  "menu": {
+    "tagline": "あなたの種子バンク",
+    "inventory": "在庫",
+    "market": "マーケット",
+    "profile": "プロフィール",
+    "chat": "チャット",
+    "wishlist": "お気に入り",
+    "following": "フォロー中",
+    "calendar": "カレンダー",
+    "settings": "設定"
+  },
+  "settings": {
+    "language": "言語",
+    "systemLanguage": "システムの言語",
+    "langEs": "Español",
+    "langEn": "English",
+    "langPt": "Português",
+    "langPtBr": "Português (Brasil)",
+    "langAst": "Asturianu",
+    "langFr": "Français",
+    "langDe": "Deutsch",
+    "langJa": "日本語",
+    "about": "このアプリについて",
+    "aboutText": "在来種のためのローカルファースト・暗号化在庫管理。AGPL-3.0。",
+    "aboutOpen": "Tane について"
+  },
+  "home": {
+    "tagline": "地域の種を分かち合い、育てよう",
+    "openMarket": "マーケット",
+    "openMarketSubtitle": "近くの種を見つけて分かち合う",
+    "yourInventory": "あなたの在庫",
+    "yourInventorySubtitle": "種を管理する"
+  }
 }