fix(gui,cli,core): offer the CAPTCHA in the browser when the web view cannot start (B195)

The verification window now runs in its own process, so the app survives
when WebKit cannot start its sandbox on secureblue, but the CAPTCHA still
could not be solved there (#29). WebKit binds the journal socket with
`--ro-bind-try`, bubblewrap only skips a missing path, not an unreadable
one, and WebKit has no switch to leave the socket out.

Proton Mail Bridge never uses a web view: it opens verify.proton.me in the
system browser and retries with the original challenge token, typed with
the offered methods. Do the same as a fallback.

- core: `browser_verification_url` and `browser_verified` build the page
  URL and the retry credential from the challenge
- gui: when the verification window fails, a dialog opens the page in the
  browser and continues the sign-in once the user is done
- cli: `pdfs login` handles a CAPTCHA the same way instead of failing
- i18n: translate the new dialog in every catalog
- docs: B195, TROUBLESHOOTING.md, ARCHITECTURE.md, changelog

Fixes #29

po/it.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: 2026-10-08 10:15+0200\n"
+"POT-Creation-Date: 2026-10-08 18:47+0200\n"
 "PO-Revision-Date: 2026-09-23 12:00+0200\n"
 "Last-Translator: Proton Drive for Linux contributors\n"
 "Language-Team: Italian\n"
@@ -271,8 +271,9 @@ msgstr ""
 #: crates/pdfs-gui/src/app/pages/locations.rs:1013
 #: crates/pdfs-gui/src/app/pages/locations.rs:1488
 #: crates/pdfs-gui/src/app/pages/locations.rs:1538
-#: crates/pdfs-gui/src/app/pages/login.rs:393
-#: crates/pdfs-gui/src/app/pages/login.rs:507
+#: crates/pdfs-gui/src/app/pages/login.rs:389
+#: crates/pdfs-gui/src/app/pages/login.rs:503
+#: crates/pdfs-gui/src/app/pages/login.rs:549
 #: crates/pdfs-gui/src/app/pages/photos.rs:2055
 #: crates/pdfs-gui/src/app/pages/shared.rs:946
 #: crates/pdfs-gui/src/app/pages/shared.rs:1027
@@ -3193,35 +3194,25 @@ msgstr "Inserisci la tua email e la password."
 msgid "Signing in…"
 msgstr "Accesso in corso…"
 
-#: crates/pdfs-gui/src/app/pages/login.rs:164
+#: crates/pdfs-gui/src/app/pages/login.rs:160
 msgid "Complete the verification to continue…"
 msgstr "Completa la verifica per continuare…"
 
-#: crates/pdfs-gui/src/app/pages/login.rs:197
+#: crates/pdfs-gui/src/app/pages/login.rs:195
 msgid "login cancelled"
 msgstr "accesso annullato"
 
-#: crates/pdfs-gui/src/app/pages/login.rs:210
-msgid ""
-"The verification page couldn't be opened, so the sign-in was cancelled. Your "
-"system may keep the web view's sandbox from starting; the troubleshooting "
-"guide explains what to do."
-msgstr ""
-"Impossibile aprire la pagina di verifica, quindi l'accesso è stato "
-"annullato. Il sistema potrebbe impedire l'avvio della sandbox della vista "
-"web; la guida alla risoluzione dei problemi spiega cosa fare."
-
-#: crates/pdfs-gui/src/app/pages/login.rs:233
+#: crates/pdfs-gui/src/app/pages/login.rs:228
 msgid "Too many sign-in attempts. Wait a few minutes and try again."
 msgstr "Troppi tentativi di accesso. Attendi qualche minuto e riprova."
 
-#: crates/pdfs-gui/src/app/pages/login.rs:239
+#: crates/pdfs-gui/src/app/pages/login.rs:234
 msgid "Couldn't reach Proton. Check your internet connection and try again."
 msgstr ""
 "Impossibile raggiungere Proton. Controlla la connessione a Internet e "
 "riprova."
 
-#: crates/pdfs-gui/src/app/pages/login.rs:242
+#: crates/pdfs-gui/src/app/pages/login.rs:237
 msgid ""
 "Signed in, but the session couldn't be saved to the system keyring. Make "
 "sure a keyring (GNOME Keyring or KWallet) is running and unlocked."
@@ -3230,24 +3221,24 @@ msgstr ""
 "portachiavi di sistema. Assicurati che un portachiavi (GNOME Keyring o "
 "KWallet) sia in esecuzione e sbloccato."
 
-#: crates/pdfs-gui/src/app/pages/login.rs:245
+#: crates/pdfs-gui/src/app/pages/login.rs:240
 msgid "Sign-in cancelled: no two-factor code was entered."
 msgstr ""
 "Accesso annullato: non è stato inserito alcun codice di autenticazione a due "
 "fattori."
 
-#: crates/pdfs-gui/src/app/pages/login.rs:248
+#: crates/pdfs-gui/src/app/pages/login.rs:243
 msgid "Sign-in cancelled: no mailbox password was entered."
 msgstr ""
 "Accesso annullato: non è stata inserita alcuna password della casella di "
 "posta."
 
-#: crates/pdfs-gui/src/app/pages/login.rs:251
+#: crates/pdfs-gui/src/app/pages/login.rs:246
 msgid "That mailbox password didn't unlock your account."
 msgstr ""
 "Quella password della casella di posta non ha sbloccato il tuo account."
 
-#: crates/pdfs-gui/src/app/pages/login.rs:254
+#: crates/pdfs-gui/src/app/pages/login.rs:249
 msgid ""
 "Sign-in cancelled: the verification wasn't completed. Sign in again to get a "
 "new one."
@@ -3256,37 +3247,37 @@ msgstr ""
 "riceverne una nuova."
 
 #. Translators: {error} is an error message, usually in English.
-#: crates/pdfs-gui/src/app/pages/login.rs:259
+#: crates/pdfs-gui/src/app/pages/login.rs:254
 #, rust-format
 msgid "Sign-in failed: {error}"
 msgstr "Accesso non riuscito: {error}"
 
-#: crates/pdfs-gui/src/app/pages/login.rs:369
+#: crates/pdfs-gui/src/app/pages/login.rs:365
 msgid "That mailbox password didn't unlock your account. Try again."
 msgstr ""
 "Quella password della casella di posta non ha sbloccato il tuo account. "
 "Riprova."
 
-#: crates/pdfs-gui/src/app/pages/login.rs:371
+#: crates/pdfs-gui/src/app/pages/login.rs:367
 msgid ""
 "This account has a separate mailbox password. Enter it to unlock your files."
 msgstr ""
 "Questo account ha una password della casella di posta separata. Inseriscila "
 "per sbloccare i tuoi file."
 
-#: crates/pdfs-gui/src/app/pages/login.rs:374
+#: crates/pdfs-gui/src/app/pages/login.rs:370
 msgid "Mailbox Password"
 msgstr "Password della casella di posta"
 
-#: crates/pdfs-gui/src/app/pages/login.rs:380
+#: crates/pdfs-gui/src/app/pages/login.rs:376
 msgid "Mailbox password"
 msgstr "Password della casella di posta"
 
-#: crates/pdfs-gui/src/app/pages/login.rs:384
+#: crates/pdfs-gui/src/app/pages/login.rs:380
 msgid "Keep unlocked on this computer"
 msgstr "Mantieni sbloccato su questo computer"
 
-#: crates/pdfs-gui/src/app/pages/login.rs:386
+#: crates/pdfs-gui/src/app/pages/login.rs:382
 msgid ""
 "Stores the unlock in the system keyring, so Proton Drive opens without "
 "asking after every login. Otherwise you enter the password once per session."
@@ -3295,49 +3286,70 @@ msgstr ""
 "chiedere dopo ogni accesso. Altrimenti inserisci la password una volta per "
 "sessione."
 
-#: crates/pdfs-gui/src/app/pages/login.rs:394
-#: crates/pdfs-gui/src/app/pages/login.rs:447
+#: crates/pdfs-gui/src/app/pages/login.rs:390
+#: crates/pdfs-gui/src/app/pages/login.rs:443
 msgid "Unlock"
 msgstr "Sblocca"
 
-#: crates/pdfs-gui/src/app/pages/login.rs:446
+#: crates/pdfs-gui/src/app/pages/login.rs:442
 msgid "Proton Drive is locked. Enter your mailbox password to unlock it."
 msgstr ""
 "Proton Drive è bloccato. Inserisci la password della casella di posta per "
 "sbloccarlo."
 
-#: crates/pdfs-gui/src/app/pages/login.rs:475
+#: crates/pdfs-gui/src/app/pages/login.rs:471
 msgid "Unlocked."
 msgstr "Sbloccato."
 
-#: crates/pdfs-gui/src/app/pages/login.rs:480
+#: crates/pdfs-gui/src/app/pages/login.rs:476
 msgid "Couldn't unlock"
 msgstr "Impossibile sbloccare"
 
-#: crates/pdfs-gui/src/app/pages/login.rs:493
+#: crates/pdfs-gui/src/app/pages/login.rs:489
 msgid "Two-Factor Authentication"
 msgstr "Autenticazione a due fattori"
 
-#: crates/pdfs-gui/src/app/pages/login.rs:495
+#: crates/pdfs-gui/src/app/pages/login.rs:491
 msgid ""
 "Enter the code from your authenticator app, or one of your recovery codes."
 msgstr ""
 "Inserisci il codice dell'app di autenticazione o uno dei tuoi codici di "
 "recupero."
 
-#: crates/pdfs-gui/src/app/pages/login.rs:501
+#: crates/pdfs-gui/src/app/pages/login.rs:497
 msgid "Authentication code"
 msgstr "Codice di autenticazione"
 
-#: crates/pdfs-gui/src/app/pages/login.rs:508
+#: crates/pdfs-gui/src/app/pages/login.rs:504
 msgid "Confirm"
 msgstr "Conferma"
 
-#: crates/pdfs-gui/src/app/pages/login.rs:536
+#: crates/pdfs-gui/src/app/pages/login.rs:535
+#
+msgid "Verify in Your Browser"
+msgstr "Verifica nel browser"
+
+#: crates/pdfs-gui/src/app/pages/login.rs:537
+msgid ""
+"The verification page can't be shown in the app on this system. Open it in "
+"your browser, complete it there, then come back and choose Continue."
+msgstr "La pagina di verifica non può essere mostrata nell’app su questo sistema. Aprila nel browser, completala lì, poi torna qui e scegli “Continua”."
+
+#: crates/pdfs-gui/src/app/pages/login.rs:543
+#
+msgid "Open Verification Page"
+msgstr "Apri pagina di verifica"
+
+#: crates/pdfs-gui/src/app/pages/login.rs:550
+#
+msgid "Continue"
+msgstr "Continua"
+
+#: crates/pdfs-gui/src/app/pages/login.rs:589
 msgid "Sign Out?"
 msgstr "Disconnettersi?"
 
-#: crates/pdfs-gui/src/app/pages/login.rs:538
+#: crates/pdfs-gui/src/app/pages/login.rs:591
 msgid ""
 "Proton Drive will disconnect and stop syncing until you sign in again. Files "
 "already on this computer stay where they are."
@@ -3345,7 +3357,7 @@ msgstr ""
 "Proton Drive si disconnetterà e interromperà la sincronizzazione finché non "
 "accedi di nuovo. I file già presenti su questo computer restano dove sono."
 
-#: crates/pdfs-gui/src/app/pages/login.rs:540
+#: crates/pdfs-gui/src/app/pages/login.rs:593
 msgid "Sign Out"
 msgstr "Disconnetti"
 
@@ -6117,6 +6129,15 @@ msgstr "{count} a"
 msgid "cannot reach the Proton Drive daemon: {error}"
 msgstr "impossibile raggiungere il demone di Proton Drive: {error}"
 
+#~ msgid ""
+#~ "The verification page couldn't be opened, so the sign-in was cancelled. "
+#~ "Your system may keep the web view's sandbox from starting; the "
+#~ "troubleshooting guide explains what to do."
+#~ msgstr ""
+#~ "Impossibile aprire la pagina di verifica, quindi l'accesso è stato "
+#~ "annullato. Il sistema potrebbe impedire l'avvio della sandbox della vista "
+#~ "web; la guida alla risoluzione dei problemi spiega cosa fare."
+
 #~ msgid "Jump to a month"
 #~ msgstr "Vai a un mese"