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/app.h

@@ -169,6 +169,7 @@ public:
     bool daemonAutoShieldActive() const { return daemon_autoshield_active_; }
     const std::string& daemonAutoShieldAddress() const { return daemon_autoshield_address_; }
     const std::string& daemonAutoShieldDisabledReason() const { return daemon_autoshield_disabled_reason_; }
+    bool daemonAutoShieldSeedRecoverable() const { return daemon_autoshield_seed_recoverable_; }
 
     // W7 QoL: a plaintext support-diagnostics snapshot (version, variant, daemon/RPC/wallet/log state)
     // for the "Copy diagnostics" action. Contains no secrets.