i18n: localize the editor toolbar in all 23 locales

The rich-text editor was the last hardcoded-English surface in the
composer: 21 tooltip titles, the eight table-menu entries, the "Remove
color" entry and the table size picker's "Pick size" label were plain
strings while every other menu in the app is localized.

All of them now come from a new email_composer.toolbar namespace,
translated into all 23 locales using each platform's established
editor terminology (Word/Docs conventions - de "Formatierung löschen",
ar "مسح التنسيق", ja "書式をクリア", ...). The link prompt stays "URL",
which is the same term in every language.

Tooltips and self-sizing dropdowns have no width constraints, so longer
translations are safe everywhere.

locales/fa/common.json

@@ -686,6 +686,38 @@
     "recipient_name_placeholder": "نام نمایشی",
     "autocomplete_search_server": "جستجو در سرور",
     "autocomplete_searching": "در حال جستجو...",
+    "toolbar": {
+      "bold": "پررنگ",
+      "italic": "کج",
+      "underline": "زیرخط‌دار",
+      "strikethrough": "خط‌خورده",
+      "text_color": "رنگ متن",
+      "remove_color": "حذف رنگ",
+      "heading_1": "سرفصل ۱",
+      "heading_2": "سرفصل ۲",
+      "bullet_list": "فهرست نشانه‌دار",
+      "ordered_list": "فهرست شماره‌دار",
+      "quote": "نقل‌قول",
+      "code_block": "بلوک کد",
+      "align_left": "تراز چپ",
+      "align_center": "وسط‌چین",
+      "align_right": "تراز راست",
+      "text_direction": "جهت متن (RTL/LTR)",
+      "link": "پیوند",
+      "table": "جدول",
+      "clear_formatting": "پاک کردن قالب‌بندی",
+      "undo": "واگرد",
+      "redo": "انجام دوباره",
+      "add_row_above": "افزودن ردیف در بالا",
+      "add_row_below": "افزودن ردیف در پایین",
+      "add_column_before": "افزودن ستون قبل",
+      "add_column_after": "افزودن ستون بعد",
+      "delete_row": "حذف ردیف",
+      "delete_column": "حذف ستون",
+      "toggle_header_row": "تغییر وضعیت ردیف سرصفحه",
+      "delete_table": "حذف جدول",
+      "pick_size": "انتخاب اندازه"
+    },
     "send_filing_warning": "ارسال شد - اما پاک‌سازی پس از ارسال ناموفق بود، ممکن است پیش‌نویس قدیمی باقی بماند."
   },
   "confirm_dialog": {