feat(lite): guided seed backup on wallet creation

Creating a wallet was one-click and silent — it never showed the seed, relying on
the user to later find Settings -> Show seed, which is an easy-to-miss fund-loss
risk. Replace the first-run prompt with a 3-step guided flow mirroring the upstream
SilentDragonXLite wizard:

  1. Welcome (Create / Restore / Later) — unchanged entry.
  2. Reveal: after createWallet, read the seed back via exportSeed and show all 24
     words (numbered grid) + the birthday, with a strong "only way to restore"
     warning, plus Copy. ("Skip" leaves the wallet created, seed backable later.)
  3. Verify: tap the words in order (shuffled chips) to confirm the backup before
     finishing; out-of-order taps are rejected with a hint.

The seed is held only for the wizard and securely wiped (sodium_memzero) on finish.
Builds clean for full-node, lite, and Windows cross-compile.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app.cpp

@@ -88,6 +88,7 @@
 #include <cstdio>
 #include <ctime>
 #include <algorithm>
+#include <random>
 #include <map>
 #include <set>
 #include <unordered_set>
@@ -1922,54 +1923,193 @@ void App::reloadThemeImages(const std::string& bgPath, const std::string& logoPa
 
 void App::renderLiteFirstRunPrompt()
 {
-    // Lite-only: a brief welcome shown when no wallet file exists yet (full-node uses the wizard,
+    // Lite-only guided onboarding (full-node uses its own wizard). Welcome -> (on create) reveal
-    // which is skipped in lite). Routes to the existing create/restore + Backup flows in Settings.
+    // the new seed + birthday with backup warnings -> verify the user wrote it down -> done.
     if (!lite_wallet_ || lite_firstrun_dismissed_) return;
-    if (lite_wallet_->walletOpen() || lite_wallet_->walletExists()) return;
+
+    // Wizard state (persists across frames). The seed is SECRET — wiped in finish().
+    static int step = 0;                 // 0 welcome, 1 reveal seed, 2 verify
+    static std::string seed;             // full seed phrase
+    static unsigned long long birthday = 0;
+    static std::vector<std::string> words;                       // correct order
+    static std::vector<std::pair<std::string, bool>> chips;      // shuffled (word, consumed)
+    static int progress = 0;             // # words confirmed in order
+    static double wrongFlashUntil = 0.0; // brief "not the next word" hint
+
+    // The welcome page is only relevant before any wallet exists; once create has started the
+    // reveal/verify (step>0), keep showing it through to completion even though the wallet is open.
+    if (step == 0 && (lite_wallet_->walletOpen() || lite_wallet_->walletExists())) return;
 
     if (!ImGui::IsPopupOpen("##LiteFirstRun")) ImGui::OpenPopup("##LiteFirstRun");
-
     ImGuiViewport* vp = ImGui::GetMainViewport();
     ImGui::SetNextWindowPos(ImVec2(vp->Pos.x + vp->Size.x * 0.5f, vp->Pos.y + vp->Size.y * 0.5f),
                             ImGuiCond_Appearing, ImVec2(0.5f, 0.5f));
+
+    auto finish = [&]() {
+        wallet::secureWipeLiteSecret(seed);
+        words.clear();
+        chips.clear();
+        progress = 0;
+        step = 0;
+        lite_firstrun_dismissed_ = true;
+        ImGui::CloseCurrentPopup();
+    };
+    auto splitWords = [](const std::string& s) {
+        std::vector<std::string> out;
+        std::string w;
+        for (char c : s) {
+            if (std::isspace(static_cast<unsigned char>(c))) { if (!w.empty()) { out.push_back(w); w.clear(); } }
+            else w.push_back(c);
+        }
+        if (!w.empty()) out.push_back(w);
+        return out;
+    };
+
     if (ImGui::BeginPopupModal("##LiteFirstRun", nullptr,
                                ImGuiWindowFlags_AlwaysAutoResize | ImGuiWindowFlags_NoTitleBar)) {
-        ImGui::PushFont(ui::material::Type().subtitle1());
-        ImGui::TextUnformatted(TR("lite_welcome_title"));
-        ImGui::PopFont();
-        ImGui::Spacing();
-        ImGui::PushTextWrapPos(ImGui::GetCursorPosX() + 360.0f);
-        ImGui::TextUnformatted(TR("lite_welcome_msg"));
-        ImGui::PopTextWrapPos();
-        ImGui::Spacing();
-        ImGui::Spacing();
-
         const float btnW = 170.0f;
-        if (ImGui::Button(TR("lite_welcome_create"), ImVec2(btnW, 0))) {
+
-            // One-click create (unencrypted by default); the user backs up the seed next via the
+        if (step == 0) {
-            // Settings → Backup & keys flow, where the seed can be revealed and copied.
+            // ── Welcome ──────────────────────────────────────────────────────────
-            const auto result = lite_wallet_->createWallet(wallet::LiteWalletCreateRequest{});
+            ImGui::PushFont(ui::material::Type().subtitle1());
-            if (result.walletReady) {
+            ImGui::TextUnformatted(TR("lite_welcome_title"));
-                ui::Notifications::instance().success(TR("lite_welcome_created"), 8.0f);
+            ImGui::PopFont();
-                setCurrentPage(ui::NavPage::Settings);
+            ImGui::Spacing();
-            } else {
+            ImGui::PushTextWrapPos(ImGui::GetCursorPosX() + 360.0f);
-                ui::Notifications::instance().warning(TR("lite_welcome_create_failed"));
+            ImGui::TextUnformatted(TR("lite_welcome_msg"));
+            ImGui::PopTextWrapPos();
+            ImGui::Spacing(); ImGui::Spacing();
+
+            if (ImGui::Button(TR("lite_welcome_create"), ImVec2(btnW, 0))) {
+                const auto result = lite_wallet_->createWallet(wallet::LiteWalletCreateRequest{});
+                if (result.walletReady) {
+                    // Read the freshly generated seed back so we can show + verify it.
+                    auto s = lite_wallet_->exportSeed();
+                    if (s.ok && !s.seedPhrase.empty()) {
+                        seed = s.seedPhrase;
+                        birthday = s.birthday;
+                        wallet::secureWipeLiteSecret(s.seedPhrase);
+                        words = splitWords(seed);
+                        step = 1;
+                    } else {
+                        // Created, but couldn't reveal the seed now — fall back to Settings backup.
+                        ui::Notifications::instance().success(TR("lite_welcome_created"), 8.0f);
+                        setCurrentPage(ui::NavPage::Settings);
+                        finish();
+                    }
+                } else {
+                    ui::Notifications::instance().warning(TR("lite_welcome_create_failed"));
+                }
+            }
+            ImGui::SameLine();
+            if (ImGui::Button(TR("lite_welcome_restore"), ImVec2(btnW, 0))) {
+                ui::Notifications::instance().info(TR("lite_welcome_restore_hint"), 8.0f);
+                setCurrentPage(ui::NavPage::Settings);
+                finish();
+            }
+            ImGui::Spacing();
+            if (ImGui::Button(TR("lite_welcome_later"),
+                              ImVec2(btnW * 2 + ImGui::GetStyle().ItemSpacing.x, 0))) {
+                finish();
+            }
+        } else if (step == 1) {
+            // ── Reveal the seed + birthday with backup warnings ─────────────────────
+            ImGui::PushFont(ui::material::Type().subtitle1());
+            ImGui::TextUnformatted("Back up your seed phrase");
+            ImGui::PopFont();
+            ImGui::Spacing();
+            ImGui::PushTextWrapPos(ImGui::GetCursorPosX() + 380.0f);
+            ImGui::PushStyleColor(ImGuiCol_Text, ui::material::Error());
+            ImGui::TextUnformatted("These 24 words are the ONLY way to restore your wallet. "
+                                   "Write them down in order, store them offline, and never share "
+                                   "them. If you lose them, your funds are gone forever.");
+            ImGui::PopStyleColor();
+            ImGui::PopTextWrapPos();
+            ImGui::Spacing();
+
+            // Numbered word grid (4 columns).
+            for (size_t i = 0; i < words.size(); ++i) {
+                char cell[96];
+                snprintf(cell, sizeof(cell), "%2zu. %s", i + 1, words[i].c_str());
+                ImGui::TextUnformatted(cell);
+                if ((i % 4) != 3 && i + 1 < words.size()) ImGui::SameLine(((i % 4) + 1) * 130.0f);
+            }
+            ImGui::Spacing();
+            char bday[80];
+            snprintf(bday, sizeof(bday), "Birthday (block height): %llu  —  back this up too.", birthday);
+            ImGui::PushStyleColor(ImGuiCol_Text, ui::material::OnSurfaceMedium());
+            ImGui::TextUnformatted(bday);
+            ImGui::PopStyleColor();
+            ImGui::Spacing(); ImGui::Spacing();
+
+            if (ImGui::Button("I've written it down", ImVec2(btnW, 0))) {
+                chips.clear();
+                for (const auto& w : words) chips.emplace_back(w, false);
+                std::mt19937 rng{std::random_device{}()};
+                std::shuffle(chips.begin(), chips.end(), rng);
+                progress = 0;
+                step = 2;
+            }
+            ImGui::SameLine();
+            if (ImGui::Button("Copy", ImVec2(80, 0))) ImGui::SetClipboardText(seed.c_str());
+            ImGui::SameLine();
+            if (ImGui::Button("Skip", ImVec2(80, 0))) {
+                ui::Notifications::instance().success(TR("lite_welcome_created"), 6.0f);
+                finish();
+            }
+        } else {  // step == 2
+            // ── Verify: tap the words in order ──────────────────────────────────────
+            ImGui::PushFont(ui::material::Type().subtitle1());
+            ImGui::TextUnformatted("Confirm your backup");
+            ImGui::PopFont();
+            ImGui::Spacing();
+            ImGui::PushTextWrapPos(ImGui::GetCursorPosX() + 380.0f);
+            ImGui::TextUnformatted("Tap the words in the correct order to confirm you saved them.");
+            ImGui::PopTextWrapPos();
+            ImGui::Spacing();
+
+            ImGui::TextDisabled("Progress: %d / %d", progress, (int)words.size());
+            if (ImGui::GetTime() < wrongFlashUntil) {
+                ImGui::SameLine();
+                ImGui::PushStyleColor(ImGuiCol_Text, ui::material::Error());
+                ImGui::TextUnformatted("  — that's not the next word");
+                ImGui::PopStyleColor();
+            }
+            ImGui::Spacing();
+
+            for (size_t i = 0; i < chips.size(); ++i) {
+                ImGui::PushID((int)i);
+                if (chips[i].second) {
+                    ImGui::BeginDisabled();
+                    ImGui::Button(chips[i].first.c_str(), ImVec2(125, 0));
+                    ImGui::EndDisabled();
+                } else if (ImGui::Button(chips[i].first.c_str(), ImVec2(125, 0))) {
+                    if (progress < (int)words.size() && chips[i].first == words[progress]) {
+                        chips[i].second = true;  // correct next word
+                        ++progress;
+                    } else {
+                        wrongFlashUntil = ImGui::GetTime() + 1.5;  // out of order
+                    }
+                }
+                ImGui::PopID();
+                if ((i % 4) != 3 && i + 1 < chips.size()) ImGui::SameLine();
+            }
+            ImGui::Spacing(); ImGui::Spacing();
+
+            const bool verified = progress == (int)words.size();
+            if (!verified) ImGui::BeginDisabled();
+            if (ImGui::Button("Done", ImVec2(btnW, 0))) {
+                ui::Notifications::instance().success("Wallet created and backed up.", 6.0f);
+                finish();
+            }
+            if (!verified) ImGui::EndDisabled();
+            ImGui::SameLine();
+            if (ImGui::Button("Back", ImVec2(80, 0))) step = 1;
+            ImGui::SameLine();
+            if (ImGui::Button("Skip", ImVec2(80, 0))) {
+                ui::Notifications::instance().success(TR("lite_welcome_created"), 6.0f);
+                finish();
             }
-            lite_firstrun_dismissed_ = true;
-            ImGui::CloseCurrentPopup();
-        }
-        ImGui::SameLine();
-        if (ImGui::Button(TR("lite_welcome_restore"), ImVec2(btnW, 0))) {
-            ui::Notifications::instance().info(TR("lite_welcome_restore_hint"), 8.0f);
-            setCurrentPage(ui::NavPage::Settings);
-            lite_firstrun_dismissed_ = true;
-            ImGui::CloseCurrentPopup();
-        }
-        ImGui::Spacing();
-        if (ImGui::Button(TR("lite_welcome_later"),
-                          ImVec2(btnW * 2 + ImGui::GetStyle().ItemSpacing.x, 0))) {
-            lite_firstrun_dismissed_ = true;
-            ImGui::CloseCurrentPopup();
         }
         ImGui::EndPopup();
     }