fix(ui): relocate + reword node auto-shield status; add chat-management FAQ entry

- Auto-shield status: the node's z_autoshieldstatus disabled_reason was echoed
  verbatim ("HD seed origin is not known-recoverable; back the seed up and pass
  -autoshield=1") and drawn INSIDE the Wallet OPTIONS checkbox grid, wedging a
  full-width line between the checkboxes. Move it to a full-width note BELOW the
  grid, and replace the raw daemon text with friendly, actionable wording keyed
  on the seed_recoverable flag (back up your seed to enable it); the raw daemon
  reason is kept on hover. Adds App::daemonAutoShieldSeedRecoverable().
- FAQ: add a Chat & Contacts entry ("How do I hide, delete, or block a
  conversation?") covering the hide / delete-revive / delete-&-block actions and
  the local-only caveat — data + i18n only, no UI code change.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/util/i18n.cpp

@@ -1274,7 +1274,9 @@ void I18n::loadBuiltinEnglish()
         strings_["wallet_recovered_restore_sub"] = "Puts your largest untouched backup back in place, verbatim, then re-scans — slightly faster, but only as complete as that one file was. Your current file is kept as a dated backup either way.";
         strings_["wallet_recovered_notify"] = "Your wallet file needed a repair — your original was safely backed up. Open the app to review your options.";
         strings_["wallet_degraded_notify"] = "Your wallet opened in reduced-function mode: existing funds are safe and spendable, but creating new addresses and shielding are disabled. Back up your seed phrase and restore it to fully repair the wallet.";
-        strings_["autoshield_by_node"] = "Auto-shield is handled by your node";
+        strings_["autoshield_by_node"] = "Your node auto-shields mined coinbase for you.";
+        strings_["autoshield_off_backup_seed"] = "Mined coinbase isn't being auto-shielded yet. Back up your seed phrase (Settings \xE2\x86\x92 Backup & Data) so your node can safely turn it on.";
+        strings_["autoshield_off_generic"] = "Your node isn't auto-shielding mined coinbase right now.";
         // In-dialog recovery lifecycle (Offer → Working → Done/Failed) + disclosures.
         strings_["wallet_recovery_working_label"] = "Working";
         strings_["wallet_recovery_done"] = "Done";
@@ -1650,6 +1652,8 @@ void I18n::loadBuiltinEnglish()
         strings_["faq_w_chat_2_a"] = "Your chat identity is derived from your wallet's recovery phrase, so it travels with your wallet \xE2\x80\x94 restore the wallet and your identity comes back. You don't create a separate account or password.";
         strings_["faq_w_chat_3_q"] = "How do contacts work?";
         strings_["faq_w_chat_3_a"] = "Add a contact by their address in the Contacts tab, optionally with a name and avatar. Contacts can be kept private to the current wallet or shared across all wallets you open on this computer.";
+        strings_["faq_w_chat_4_q"] = "How do I hide, delete, or block a conversation?";
+        strings_["faq_w_chat_4_a"] = "Open a conversation and use the icons in its header. Hide (the eye) drops it from the list but keeps every message \xE2\x80\x94 a new message un-hides it. Delete (the trash) opens a dialog: 'Delete' clears the history on this device (if that person messages you again, the conversation comes back), while 'Delete & block' also stops their future messages until you unblock them from the 'Blocked' list above the conversation list. Everything here is local to this device \xE2\x80\x94 the messages stay on the blockchain and the other person keeps their own copy, so it isn't an 'unsend'.";
 
         // Wallet > Settings & Appearance
         strings_["faq_w_set_1_q"] = "How do I change the theme?";