fix(cli,core,fuse,gui): say why the mount keeps failing, and back off

A mount that failed on every try retried every 5 s forever, and the
reason was only in the journal: the app and the tray said Connecting...
for days (B263, issue #40). The retry now doubles to a 2-minute ceiling,
and the last failure is kept in mount-failure.json for the app, the
tray, pdfs diagnose and systemctl status.

The early returns in mount left the workers they had started running
beside the next attempt (B264). They are now stopped on every error
path, without telling systemd the daemon is stopping.

po/pt_BR.po

@@ -5,7 +5,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: proton-drive-linux 2.1.0\n"
 "Report-Msgid-Bugs-To: https://github.com/narrrl/proton-drive-linux/issues\n"
-"POT-Creation-Date: 2026-10-26 22:26+0100\n"
+"POT-Creation-Date: 2026-10-31 10:37+0100\n"
 "PO-Revision-Date: 2026-09-23 12:00+0200\n"
 "Last-Translator: Proton Drive for Linux contributors\n"
 "Language-Team: Portuguese (Brazil)\n"
@@ -420,14 +420,25 @@ msgstr "Não conectado"
 msgid "The Proton Drive service isn't running."
 msgstr "O serviço do Proton Drive não está em execução."
 
-#: crates/pdfs-gui/src/app/main.rs:1803
+#: crates/pdfs-gui/src/app/main.rs:1813
+msgid "Can't open your Drive"
+msgstr "Não foi possível abrir o Proton Drive"
+
+#: crates/pdfs-gui/src/app/main.rs:1816
+#, rust-format
+msgid ""
+"The Proton Drive service keeps failing to start and tries again on its own. "
+"The last error was: {error}"
+msgstr "O serviço do Proton Drive não consegue iniciar e tenta de novo sozinho. Último erro: {error}"
+
+#: crates/pdfs-gui/src/app/main.rs:1824
 #: crates/pdfs-gui/src/app/pages/status.rs:355
 #: crates/pdfs-gui/src/hud/mod.rs:269 crates/pdfs-gui/src/hud/mod.rs:579
-#: crates/pdfs-gui/src/main.rs:475 crates/pdfs-gui/src/main.rs:517
+#: crates/pdfs-gui/src/main.rs:493 crates/pdfs-gui/src/main.rs:535
 msgid "Connecting…"
 msgstr "Conectando…"
 
-#: crates/pdfs-gui/src/app/main.rs:1804
+#: crates/pdfs-gui/src/app/main.rs:1825
 msgid "Waiting for the Proton Drive service to start."
 msgstr "Aguardando o serviço do Proton Drive iniciar."
 
@@ -2892,7 +2903,7 @@ msgid "Sync paused until you resume"
 msgstr "Sincronização pausada até você retomar"
 
 #: crates/pdfs-gui/src/app/pages/locations.rs:570
-#: crates/pdfs-gui/src/app/pages/status.rs:1445 crates/pdfs-gui/src/main.rs:290
+#: crates/pdfs-gui/src/app/pages/status.rs:1445 crates/pdfs-gui/src/main.rs:308
 msgid "Sync paused"
 msgstr "Sincronização pausada"
 
@@ -5093,7 +5104,7 @@ msgstr "Retoma {time}"
 msgid "Until you resume"
 msgstr "Até você retomar"
 
-#: crates/pdfs-gui/src/app/pages/status.rs:1464 crates/pdfs-gui/src/main.rs:292
+#: crates/pdfs-gui/src/app/pages/status.rs:1464 crates/pdfs-gui/src/main.rs:310
 #, rust-format
 msgid "{n} change needs attention"
 msgid_plural "{n} changes need attention"
@@ -6324,52 +6335,57 @@ msgstr "O Proton Drive não está respondendo"
 msgid "Signed in as {username} — locked"
 msgstr "Conectado como {username} — bloqueado"
 
-#: crates/pdfs-gui/src/main.rs:200
+#: crates/pdfs-gui/src/main.rs:209
+#, rust-format
+msgid "Signed in as {username} — can't open your Drive"
+msgstr "Conectado como {username} — não foi possível abrir o Proton Drive"
+
+#: crates/pdfs-gui/src/main.rs:218
 #, rust-format
 msgid "Signed in as {username} — not connected"
 msgstr "Conectado como {username} — sem conexão"
 
-#: crates/pdfs-gui/src/main.rs:205
+#: crates/pdfs-gui/src/main.rs:223
 msgid "Not signed in"
 msgstr "Não conectado"
 
 #. Translators: {error} is an error message, in English.
-#: crates/pdfs-gui/src/main.rs:208
+#: crates/pdfs-gui/src/main.rs:226
 #, rust-format
 msgid "Error: {error}"
 msgstr "Erro: {error}"
 
-#: crates/pdfs-gui/src/main.rs:230
+#: crates/pdfs-gui/src/main.rs:248
 msgid "Proton Drive sent an unexpected reply"
 msgstr "O Proton Drive enviou uma resposta inesperada"
 
-#: crates/pdfs-gui/src/main.rs:284
+#: crates/pdfs-gui/src/main.rs:302
 msgid "Session expired — sign in again"
 msgstr "Sessão expirada — entre novamente"
 
-#: crates/pdfs-gui/src/main.rs:286
+#: crates/pdfs-gui/src/main.rs:304
 msgid "Sign-in not saved — unlock your keyring"
 msgstr "Login não salvo — desbloqueie o chaveiro"
 
-#: crates/pdfs-gui/src/main.rs:289
+#: crates/pdfs-gui/src/main.rs:307
 msgid "Update not finished — restart Proton Drive"
 msgstr "Atualização não concluída — reinicie o Proton Drive"
 
-#: crates/pdfs-gui/src/main.rs:299
+#: crates/pdfs-gui/src/main.rs:317
 #, rust-format
 msgid "Up to date in {mountpoint} ({n} pinned)"
 msgid_plural "Up to date in {mountpoint} ({n} pinned)"
 msgstr[0] "Atualizado em {mountpoint} ({n} fixado)"
 msgstr[1] "Atualizado em {mountpoint} ({n} fixados)"
 
-#: crates/pdfs-gui/src/main.rs:306
+#: crates/pdfs-gui/src/main.rs:324
 #, rust-format
 msgid "Syncing — {queued} ({n} pinned)"
 msgid_plural "Syncing — {queued} ({n} pinned)"
 msgstr[0] "Sincronizando — {queued} ({n} fixado)"
 msgstr[1] "Sincronizando — {queued} ({n} fixados)"
 
-#: crates/pdfs-gui/src/main.rs:313
+#: crates/pdfs-gui/src/main.rs:331
 #, rust-format
 msgid "Offline — cached files only ({n} pinned)"
 msgid_plural "Offline — cached files only ({n} pinned)"
@@ -6377,60 +6393,60 @@ msgstr[0] "Offline — somente arquivos em cache ({n} fixado)"
 msgstr[1] "Offline — somente arquivos em cache ({n} fixados)"
 
 #. Translators: {queued} is a queue summary such as "3 uploads queued".
-#: crates/pdfs-gui/src/main.rs:319
+#: crates/pdfs-gui/src/main.rs:337
 #, rust-format
 msgid "Offline — {queued}"
 msgstr "Offline — {queued}"
 
 #. Translators: a menu item that opens the list of failing changes.
-#: crates/pdfs-gui/src/main.rs:358
+#: crates/pdfs-gui/src/main.rs:376
 #, rust-format
 msgid "{n} issue — View"
 msgid_plural "{n} issues — View"
 msgstr[0] "{n} problema — Ver"
 msgstr[1] "{n} problemas — Ver"
 
-#: crates/pdfs-gui/src/main.rs:465
+#: crates/pdfs-gui/src/main.rs:483
 msgid "Sign In…"
 msgstr "Entrar…"
 
-#: crates/pdfs-gui/src/main.rs:466
+#: crates/pdfs-gui/src/main.rs:484
 msgid "Sign In Again…"
 msgstr "Entrar novamente…"
 
-#: crates/pdfs-gui/src/main.rs:469
+#: crates/pdfs-gui/src/main.rs:487
 msgid "Open Proton Drive"
 msgstr "Abrir o Proton Drive"
 
-#: crates/pdfs-gui/src/main.rs:473
+#: crates/pdfs-gui/src/main.rs:491
 msgid "Restart Proton Drive"
 msgstr "Reiniciar o Proton Drive"
 
-#: crates/pdfs-gui/src/main.rs:482
+#: crates/pdfs-gui/src/main.rs:500
 msgid "Open Folder"
 msgstr "Abrir pasta"
 
-#: crates/pdfs-gui/src/main.rs:494
+#: crates/pdfs-gui/src/main.rs:512
 msgid "Resume Sync"
 msgstr "Retomar sincronização"
 
-#: crates/pdfs-gui/src/main.rs:496
+#: crates/pdfs-gui/src/main.rs:514
 msgid "Pause Sync"
 msgstr "Pausar sincronização"
 
-#: crates/pdfs-gui/src/main.rs:515
+#: crates/pdfs-gui/src/main.rs:533
 msgid "Connect"
 msgstr "Conectar"
 
-#: crates/pdfs-gui/src/main.rs:522
+#: crates/pdfs-gui/src/main.rs:540
 msgid "Hide Tray Icon"
 msgstr "Ocultar ícone da bandeja"
 
-#: crates/pdfs-gui/src/main.rs:526
+#: crates/pdfs-gui/src/main.rs:544
 msgid "Stop Proton Drive…"
 msgstr "Parar o Proton Drive…"
 
-#: crates/pdfs-gui/src/main.rs:530
+#: crates/pdfs-gui/src/main.rs:548
 msgid "Quit"
 msgstr "Sair"