Fix: stop resurrecting deleted rows in the mailbox refresh merge

Fixes #592.

refreshCurrentMailbox merges the refreshed first page with the already
loaded list, appending existing entries beyond a cutoff. That cutoff
was derived from the refreshed list's length - so whenever a folder
shrank, the fresh page was shorter than the stale list and the loop
re-appended the deleted rows from stale local state, despite the
comment right above promising the opposite.

The visible result is the reported bug: after sending a draft, the
Drafts view keeps showing a ghost row for the already-destroyed draft.
The send actually succeeded - resending the ghost delivers the mail
again, which we reproduced with a live JMAP trace: four successful
submissions, an empty server-side Drafts folder, a notFound ghost id,
and five delivered copies. Deriving the cutoff from the page size
fixes the shrink case while preserving the merge's intent for
arrivals and loaded deeper pages; regression tests cover all three
shapes.

Also surface post-send filing failures instead of dropping them, as
flagged in 4dc76bbb's follow-up note: a rejected onSuccessUpdateEmail
patch or old-draft destroy now logs the server's error details and
returns a filingError on SendEmailResult, and the UI shows a warning
toast (all 23 locales) so a stale draft row is never again mistaken
for a failed send. A plugin veto of the send leaves a debug trace.

locales/ar/common.json

@@ -685,7 +685,8 @@
     "recipient_email_placeholder": "عنوان البريد الإلكتروني",
     "recipient_name_placeholder": "الاسم المعروض",
     "autocomplete_search_server": "البحث في الخادم",
-    "autocomplete_searching": "جارٍ البحث..."
+    "autocomplete_searching": "جارٍ البحث...",
+    "send_filing_warning": "تم الإرسال - لكن التنظيف بعد الإرسال فشل، وقد تبقى مسودة قديمة."
   },
   "confirm_dialog": {
     "confirm": "تأكيد",

locales/cs/common.json

@@ -685,7 +685,8 @@
     "recipient_email_placeholder": "E-mailová adresa",
     "recipient_name_placeholder": "Zobrazované jméno",
     "autocomplete_search_server": "Hledat na serveru",
-    "autocomplete_searching": "Hledání..."
+    "autocomplete_searching": "Hledání...",
+    "send_filing_warning": "Odesláno - ale následný úklid selhal, může zůstat zastaralý koncept."
   },
   "confirm_dialog": {
     "confirm": "Potvrdit",

locales/da/common.json

@@ -685,7 +685,8 @@
     "recipient_email_placeholder": "E-mailadresse",
     "recipient_name_placeholder": "Visningsnavn",
     "autocomplete_search_server": "Søg på serveren",
-    "autocomplete_searching": "Søger..."
+    "autocomplete_searching": "Søger...",
+    "send_filing_warning": "Sendt - men oprydningen bagefter mislykkedes, en forældet kladde kan blive stående."
   },
   "confirm_dialog": {
     "confirm": "Bekræft",

locales/de/common.json

@@ -685,7 +685,8 @@
     "recipient_email_placeholder": "E-Mail-Adresse",
     "recipient_name_placeholder": "Anzeigename",
     "autocomplete_search_server": "Auf dem Server suchen",
-    "autocomplete_searching": "Suche läuft..."
+    "autocomplete_searching": "Suche läuft...",
+    "send_filing_warning": "Gesendet - aber das Aufräumen danach schlug fehl, evtl. bleibt ein alter Entwurf sichtbar."
   },
   "confirm_dialog": {
     "confirm": "Bestätigen",

locales/en/common.json

@@ -685,7 +685,8 @@
     "recipient_email_placeholder": "Email address",
     "recipient_name_placeholder": "Display name",
     "autocomplete_search_server": "Search the server",
-    "autocomplete_searching": "Searching..."
+    "autocomplete_searching": "Searching...",
+    "send_filing_warning": "Sent - but the post-send cleanup failed, a stale draft may remain."
   },
   "confirm_dialog": {
     "confirm": "Confirm",

locales/es/common.json

@@ -685,7 +685,8 @@
     "recipient_email_placeholder": "Dirección de correo",
     "recipient_name_placeholder": "Nombre para mostrar",
     "autocomplete_search_server": "Buscar en el servidor",
-    "autocomplete_searching": "Buscando..."
+    "autocomplete_searching": "Buscando...",
+    "send_filing_warning": "Enviado - pero la limpieza posterior falló, puede quedar un borrador obsoleto."
   },
   "confirm_dialog": {
     "confirm": "Confirmar",

locales/fa/common.json

@@ -685,7 +685,8 @@
     "recipient_email_placeholder": "آدرس ایمیل",
     "recipient_name_placeholder": "نام نمایشی",
     "autocomplete_search_server": "جستجو در سرور",
-    "autocomplete_searching": "در حال جستجو..."
+    "autocomplete_searching": "در حال جستجو...",
+    "send_filing_warning": "ارسال شد - اما پاک‌سازی پس از ارسال ناموفق بود، ممکن است پیش‌نویس قدیمی باقی بماند."
   },
   "confirm_dialog": {
     "confirm": "تأیید",

locales/fr/common.json

@@ -685,7 +685,8 @@
     "recipient_email_placeholder": "Adresse e-mail",
     "recipient_name_placeholder": "Nom d'affichage",
     "autocomplete_search_server": "Rechercher sur le serveur",
-    "autocomplete_searching": "Recherche en cours..."
+    "autocomplete_searching": "Recherche en cours...",
+    "send_filing_warning": "Envoyé - mais le nettoyage après envoi a échoué, un ancien brouillon peut subsister."
   },
   "confirm_dialog": {
     "confirm": "Confirmer",

locales/he/common.json

@@ -650,7 +650,8 @@
     "recipient_email_placeholder": "כתובת דוא״ל",
     "recipient_name_placeholder": "שם תצוגה",
     "autocomplete_search_server": "חיפוש בשרת",
-    "autocomplete_searching": "מחפש..."
+    "autocomplete_searching": "מחפש...",
+    "send_filing_warning": "נשלח - אך הניקוי שלאחר השליחה נכשל, ייתכן שתישאר טיוטה ישנה."
   },
   "confirm_dialog": {
     "confirm": "אשר",

locales/hu/common.json

@@ -685,7 +685,8 @@
     "recipient_email_placeholder": "E-mail-cím",
     "recipient_name_placeholder": "Megjelenített név",
     "autocomplete_search_server": "Keresés a kiszolgálón",
-    "autocomplete_searching": "Keresés..."
+    "autocomplete_searching": "Keresés...",
+    "send_filing_warning": "Elküldve - de az utólagos rendrakás nem sikerült, egy elavult piszkozat megmaradhat."
   },
   "confirm_dialog": {
     "confirm": "Megerősítés",

locales/it/common.json

@@ -685,7 +685,8 @@
     "recipient_email_placeholder": "Indirizzo email",
     "recipient_name_placeholder": "Nome visualizzato",
     "autocomplete_search_server": "Cerca nel server",
-    "autocomplete_searching": "Ricerca in corso..."
+    "autocomplete_searching": "Ricerca in corso...",
+    "send_filing_warning": "Inviato - ma la pulizia successiva non è riuscita, potrebbe restare una bozza obsoleta."
   },
   "confirm_dialog": {
     "confirm": "Conferma",

locales/ja/common.json

@@ -685,7 +685,8 @@
     "recipient_email_placeholder": "メールアドレス",
     "recipient_name_placeholder": "表示名",
     "autocomplete_search_server": "サーバーを検索",
-    "autocomplete_searching": "検索中..."
+    "autocomplete_searching": "検索中...",
+    "send_filing_warning": "送信されましたが、送信後の整理に失敗しました。古い下書きが残る場合があります。"
   },
   "confirm_dialog": {
     "confirm": "確認",

locales/ko/common.json

@@ -685,7 +685,8 @@
     "recipient_email_placeholder": "이메일 주소",
     "recipient_name_placeholder": "표시 이름",
     "autocomplete_search_server": "서버에서 검색",
-    "autocomplete_searching": "검색 중..."
+    "autocomplete_searching": "검색 중...",
+    "send_filing_warning": "보냈지만 전송 후 정리에 실패했습니다. 오래된 임시 보관 메일이 남아 있을 수 있습니다."
   },
   "confirm_dialog": {
     "confirm": "확인",

locales/lv/common.json

@@ -685,7 +685,8 @@
     "recipient_email_placeholder": "E-pasta adrese",
     "recipient_name_placeholder": "Parādāmais vārds",
     "autocomplete_search_server": "Meklēt serverī",
-    "autocomplete_searching": "Meklē..."
+    "autocomplete_searching": "Meklē...",
+    "send_filing_warning": "Nosūtīts - bet pēcapstrāde neizdevās, var palikt novecojis melnraksts."
   },
   "confirm_dialog": {
     "confirm": "Apstiprināt",

locales/nl/common.json

@@ -685,7 +685,8 @@
     "recipient_email_placeholder": "E-mailadres",
     "recipient_name_placeholder": "Weergavenaam",
     "autocomplete_search_server": "Op de server zoeken",
-    "autocomplete_searching": "Bezig met zoeken..."
+    "autocomplete_searching": "Bezig met zoeken...",
+    "send_filing_warning": "Verzonden - maar het opruimen daarna is mislukt, mogelijk blijft een oud concept staan."
   },
   "confirm_dialog": {
     "confirm": "Bevestigen",

locales/pl/common.json

@@ -685,7 +685,8 @@
     "recipient_email_placeholder": "Adres e-mail",
     "recipient_name_placeholder": "Wyświetlana nazwa",
     "autocomplete_search_server": "Szukaj na serwerze",
-    "autocomplete_searching": "Wyszukiwanie..."
+    "autocomplete_searching": "Wyszukiwanie...",
+    "send_filing_warning": "Wysłano - ale późniejsze porządkowanie nie powiodło się, może pozostać nieaktualna wersja robocza."
   },
   "confirm_dialog": {
     "confirm": "Potwierdź",

locales/pt/common.json

@@ -685,7 +685,8 @@
     "recipient_email_placeholder": "Endereço de e-mail",
     "recipient_name_placeholder": "Nome de exibição",
     "autocomplete_search_server": "Pesquisar no servidor",
-    "autocomplete_searching": "Pesquisando..."
+    "autocomplete_searching": "Pesquisando...",
+    "send_filing_warning": "Enviado - mas a limpeza posterior falhou, um rascunho antigo pode permanecer."
   },
   "confirm_dialog": {
     "confirm": "Confirmar",

locales/ro/common.json

@@ -685,7 +685,8 @@
     "recipient_email_placeholder": "Adresă de e-mail",
     "recipient_name_placeholder": "Numele afișat",
     "autocomplete_search_server": "Caută pe server",
-    "autocomplete_searching": "Se caută..."
+    "autocomplete_searching": "Se caută...",
+    "send_filing_warning": "Trimis - dar curățarea ulterioară a eșuat, poate rămâne o ciornă veche."
   },
   "confirm_dialog": {
     "confirm": "Confirmare",

locales/ru/common.json

@@ -685,7 +685,8 @@
     "recipient_email_placeholder": "Адрес эл. почты",
     "recipient_name_placeholder": "Отображаемое имя",
     "autocomplete_search_server": "Искать на сервере",
-    "autocomplete_searching": "Поиск..."
+    "autocomplete_searching": "Поиск...",
+    "send_filing_warning": "Отправлено - но последующая очистка не удалась, может остаться устаревший черновик."
   },
   "confirm_dialog": {
     "confirm": "Подтвердить",

locales/sk/common.json

@@ -685,7 +685,8 @@
     "recipient_email_placeholder": "E-mailová adresa",
     "recipient_name_placeholder": "Zobrazené meno",
     "autocomplete_search_server": "Hľadať na serveri",
-    "autocomplete_searching": "Hľadanie..."
+    "autocomplete_searching": "Hľadanie...",
+    "send_filing_warning": "Odoslané - ale následné upratovanie zlyhalo, môže zostať zastaraný koncept."
   },
   "confirm_dialog": {
     "confirm": "Potvrdiť",

locales/tr/common.json

@@ -685,7 +685,8 @@
     "recipient_email_placeholder": "E-posta adresi",
     "recipient_name_placeholder": "Görünen ad",
     "autocomplete_search_server": "Sunucuda ara",
-    "autocomplete_searching": "Aranıyor..."
+    "autocomplete_searching": "Aranıyor...",
+    "send_filing_warning": "Gönderildi - ancak sonrasındaki temizleme başarısız oldu, eski bir taslak kalabilir."
   },
   "confirm_dialog": {
     "confirm": "Onayla",

locales/uk/common.json

@@ -685,7 +685,8 @@
     "recipient_email_placeholder": "Адреса ел. пошти",
     "recipient_name_placeholder": "Відображуване ім'я",
     "autocomplete_search_server": "Шукати на сервері",
-    "autocomplete_searching": "Пошук..."
+    "autocomplete_searching": "Пошук...",
+    "send_filing_warning": "Надіслано - але подальше очищення не вдалося, може залишитися застаріла чернетка."
   },
   "confirm_dialog": {
     "confirm": "Підтвердити",

locales/zh/common.json

@@ -685,7 +685,8 @@
     "recipient_email_placeholder": "电子邮件地址",
     "recipient_name_placeholder": "显示名称",
     "autocomplete_search_server": "在服务器上搜索",
-    "autocomplete_searching": "搜索中..."
+    "autocomplete_searching": "搜索中...",
+    "send_filing_warning": "已发送，但发送后的清理失败，可能会残留旧草稿。"
   },
   "confirm_dialog": {
     "confirm": "确认",