fix: Tier-2 mediums — input trims, confirmations, amount normalization

More robustness fixes from the audit (the import-key pattern, lower severity):

- Trim pasted input before use/validation: network add-server URL/label,
  lite-wallet key import (+ block empty), validate-address, address-book entry.
- Confirmations for destructive/irreversible actions:
  - Address-book Delete now needs a confirming second click (no undo).
  - Console `stop` needs a confirming second `stop` (it shuts down the node).
  - Wizard "Skip" encryption needs a confirming second click (keys stored
    unencrypted).
- Send amount: normalize to 8dp (satoshi precision) on both the DRGX and USD
  inputs so digits past 8dp aren't silently dropped between the preview/review
  and what's actually sent.

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

src/ui/pages/settings_page.cpp

@@ -1741,10 +1741,17 @@ void RenderSettingsPage(App* app) {
                                          ImGuiInputTextFlags_Password);
                         ImGui::SetCursorScreenPos(ImVec2(leftX, ImGui::GetCursorScreenPos().y));
                         if (TactileButton(TrId("lite_import", "LiteImportKeyBtn").c_str(), ImVec2(0, 0), S.resolveFont("button"))) {
-                            const auto r = app->liteWallet()->importKey(s_settingsState.lite_import_key);
-                            sodium_memzero(s_settingsState.lite_import_key, sizeof(s_settingsState.lite_import_key));
-                            s_settingsState.lite_backup_status =
-                                r.ok ? TR("lite_key_imported") : r.error;
+                            std::string liteKey(s_settingsState.lite_import_key);
+                            while (!liteKey.empty() && (liteKey.front()==' '||liteKey.front()=='\t'||liteKey.front()=='\n'||liteKey.front()=='\r')) liteKey.erase(liteKey.begin());
+                            while (!liteKey.empty() && (liteKey.back()==' '||liteKey.back()=='\t'||liteKey.back()=='\n'||liteKey.back()=='\r')) liteKey.pop_back();
+                            if (liteKey.empty()) {
+                                s_settingsState.lite_backup_status = "Enter a private key to import.";
+                            } else {
+                                const auto r = app->liteWallet()->importKey(liteKey);
+                                sodium_memzero(s_settingsState.lite_import_key, sizeof(s_settingsState.lite_import_key));
+                                s_settingsState.lite_backup_status =
+                                    r.ok ? TR("lite_key_imported") : r.error;
+                            }
                         }
 
                         if (!s_settingsState.lite_backup_status.empty()) {