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/nl.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: Dutch\n"
@@ -421,14 +421,25 @@ msgstr "Niet verbonden"
 msgid "The Proton Drive service isn't running."
 msgstr "De Proton Drive-service draait niet."
 
-#: crates/pdfs-gui/src/app/main.rs:1803
+#: crates/pdfs-gui/src/app/main.rs:1813
+msgid "Can't open your Drive"
+msgstr "Kan Proton Drive niet openen"
+
+#: 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 "De Proton Drive-service kan steeds niet starten en probeert het zelf opnieuw. Laatste fout: {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 "Verbinden…"
 
-#: 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 "Wachten tot de Proton Drive-service is gestart."
 
@@ -2896,7 +2907,7 @@ msgid "Sync paused until you resume"
 msgstr "Synchronisatie gepauzeerd totdat je hervat"
 
 #: 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 "Synchronisatie gepauzeerd"
 
@@ -5108,7 +5119,7 @@ msgstr "Hervat {time}"
 msgid "Until you resume"
 msgstr "Totdat je hervat"
 
-#: 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"
@@ -6337,52 +6348,57 @@ msgstr "Proton Drive reageert niet"
 msgid "Signed in as {username} — locked"
 msgstr "Aangemeld als {username} — vergrendeld"
 
-#: 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 "Aangemeld als {username} — kan Proton Drive niet openen"
+
+#: crates/pdfs-gui/src/main.rs:218
 #, rust-format
 msgid "Signed in as {username} — not connected"
 msgstr "Aangemeld als {username} — niet verbonden"
 
-#: crates/pdfs-gui/src/main.rs:205
+#: crates/pdfs-gui/src/main.rs:223
 msgid "Not signed in"
 msgstr "Niet aangemeld"
 
 #. 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 "Fout: {error}"
 
-#: crates/pdfs-gui/src/main.rs:230
+#: crates/pdfs-gui/src/main.rs:248
 msgid "Proton Drive sent an unexpected reply"
 msgstr "Proton Drive gaf een onverwacht antwoord"
 
-#: crates/pdfs-gui/src/main.rs:284
+#: crates/pdfs-gui/src/main.rs:302
 msgid "Session expired — sign in again"
 msgstr "Sessie verlopen — meld je opnieuw aan"
 
-#: crates/pdfs-gui/src/main.rs:286
+#: crates/pdfs-gui/src/main.rs:304
 msgid "Sign-in not saved — unlock your keyring"
 msgstr "Aanmelding niet opgeslagen — ontgrendel je sleutelbos"
 
-#: crates/pdfs-gui/src/main.rs:289
+#: crates/pdfs-gui/src/main.rs:307
 msgid "Update not finished — restart Proton Drive"
 msgstr "Update niet voltooid — start Proton Drive opnieuw"
 
-#: 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] "Bijgewerkt in {mountpoint} ({n} vastgezet)"
 msgstr[1] "Bijgewerkt in {mountpoint} ({n} vastgezet)"
 
-#: 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] "Synchroniseren — {queued} ({n} vastgezet)"
 msgstr[1] "Synchroniseren — {queued} ({n} vastgezet)"
 
-#: 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)"
@@ -6390,60 +6406,60 @@ msgstr[0] "Offline — alleen bestanden in cache ({n} vastgezet)"
 msgstr[1] "Offline — alleen bestanden in cache ({n} vastgezet)"
 
 #. 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} probleem — Bekijken"
 msgstr[1] "{n} problemen — Bekijken"
 
-#: crates/pdfs-gui/src/main.rs:465
+#: crates/pdfs-gui/src/main.rs:483
 msgid "Sign In…"
 msgstr "Aanmelden…"
 
-#: crates/pdfs-gui/src/main.rs:466
+#: crates/pdfs-gui/src/main.rs:484
 msgid "Sign In Again…"
 msgstr "Opnieuw aanmelden…"
 
-#: crates/pdfs-gui/src/main.rs:469
+#: crates/pdfs-gui/src/main.rs:487
 msgid "Open Proton Drive"
 msgstr "Proton Drive openen"
 
-#: crates/pdfs-gui/src/main.rs:473
+#: crates/pdfs-gui/src/main.rs:491
 msgid "Restart Proton Drive"
 msgstr "Proton Drive opnieuw starten"
 
-#: crates/pdfs-gui/src/main.rs:482
+#: crates/pdfs-gui/src/main.rs:500
 msgid "Open Folder"
 msgstr "Map openen"
 
-#: crates/pdfs-gui/src/main.rs:494
+#: crates/pdfs-gui/src/main.rs:512
 msgid "Resume Sync"
 msgstr "Synchronisatie hervatten"
 
-#: crates/pdfs-gui/src/main.rs:496
+#: crates/pdfs-gui/src/main.rs:514
 msgid "Pause Sync"
 msgstr "Synchronisatie pauzeren"
 
-#: crates/pdfs-gui/src/main.rs:515
+#: crates/pdfs-gui/src/main.rs:533
 msgid "Connect"
 msgstr "Verbinden"
 
-#: crates/pdfs-gui/src/main.rs:522
+#: crates/pdfs-gui/src/main.rs:540
 msgid "Hide Tray Icon"
 msgstr "Pictogram in systeemvak verbergen"
 
-#: crates/pdfs-gui/src/main.rs:526
+#: crates/pdfs-gui/src/main.rs:544
 msgid "Stop Proton Drive…"
 msgstr "Proton Drive stoppen…"
 
-#: crates/pdfs-gui/src/main.rs:530
+#: crates/pdfs-gui/src/main.rs:548
 msgid "Quit"
 msgstr "Afsluiten"