feat(chat): hide conversations + contact address picker for new conversation

Hide conversations:
- A "Hide" action in the thread header drops a conversation from the list. The
  messages stay in the seed-encrypted store (on-chain history can't be deleted);
  a new INCOMING message un-hides it (you can't un-receive), so nothing is lost.
- Hidden cids persist in settings (mirrors the mute list) and are skipped by both
  the conversation list and the unread badge.

New-conversation address picker:
- A "Choose from contacts" dropdown lists the address book's shielded (z-address)
  contacts and fills the recipient field on selection; manual paste still works.

8-language strings + CJK subset (+1 glyph 届).

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

src/app_network.cpp

@@ -1262,6 +1262,7 @@ int App::chatUnreadCount() const
     const auto& store = chat_service_.store();
     for (const auto& cid : store.conversationIds()) {
         if (settings_ && settings_->isChatMuted(cid)) continue;   // muted conversations don't badge (Q10)
+        if (settings_ && settings_->isChatHidden(cid)) continue;  // hidden conversations don't badge
         std::int64_t seen = 0;
         const auto it = chat_seen_watermark_.find(cid);
         if (it != chat_seen_watermark_.end()) seen = it->second;
@@ -1719,6 +1720,13 @@ void App::refreshTransactionData()
                 for (const auto& tx : result.transactions) chatTxTimes[tx.txid] = tx.timestamp;
                 std::vector<std::string> newChatCids;
                 chat_service_.ingest(result.hushChatMetadata, chatTxTimes, std::time(nullptr), &newChatCids);
+                // A new message un-hides a hidden conversation (you can't un-receive), so nothing is lost.
+                if (settings_) {
+                    bool unhid = false;
+                    for (const auto& cid : newChatCids)
+                        if (settings_->isChatHidden(cid)) { settings_->setChatHidden(cid, false); unhid = true; }
+                    if (unhid) settings_->save();
+                }
                 // Toast when a NON-muted conversation received a new message and we're off the Chat tab.
                 // Gate on the ingest-reported cids, not a seen-watermark delta — the latter can be swallowed
                 // by block-time vs wall-clock (echo) skew (Q10 + Q4).
@@ -1785,6 +1793,13 @@ void App::refreshRecentTransactionData()
                 for (const auto& tx : result.transactions) chatTxTimes[tx.txid] = tx.timestamp;
                 std::vector<std::string> newChatCids;
                 chat_service_.ingest(result.hushChatMetadata, chatTxTimes, std::time(nullptr), &newChatCids);
+                // A new message un-hides a hidden conversation (you can't un-receive), so nothing is lost.
+                if (settings_) {
+                    bool unhid = false;
+                    for (const auto& cid : newChatCids)
+                        if (settings_->isChatHidden(cid)) { settings_->setChatHidden(cid, false); unhid = true; }
+                    if (unhid) settings_->save();
+                }
                 // Toast when a NON-muted conversation received a new message and we're off the Chat tab.
                 // Gate on the ingest-reported cids, not a seen-watermark delta — the latter can be swallowed
                 // by block-time vs wall-clock (echo) skew (Q10 + Q4).

src/config/settings.cpp

@@ -152,6 +152,11 @@ bool Settings::load(const std::string& path)
             for (const auto& c : j["muted_chat_cids"])
                 if (c.is_string()) muted_chat_cids_.push_back(c.get<std::string>());
         }
+        if (j.contains("hidden_chat_cids") && j["hidden_chat_cids"].is_array()) {
+            hidden_chat_cids_.clear();
+            for (const auto& c : j["hidden_chat_cids"])
+                if (c.is_string()) hidden_chat_cids_.push_back(c.get<std::string>());
+        }
         loadScalar(j, "acrylic_enabled", acrylic_enabled_);
         loadScalar(j, "acrylic_quality", acrylic_quality_);
         loadScalar(j, "blur_multiplier", blur_multiplier_);
@@ -430,6 +435,9 @@ bool Settings::save(const std::string& path)
     j["muted_chat_cids"] = json::array();
     for (const auto& c : muted_chat_cids_)
         j["muted_chat_cids"].push_back(c);
+    j["hidden_chat_cids"] = json::array();
+    for (const auto& c : hidden_chat_cids_)
+        j["hidden_chat_cids"].push_back(c);
     j["acrylic_enabled"] = acrylic_enabled_;
     j["acrylic_quality"] = acrylic_quality_;
     j["blur_multiplier"] = blur_multiplier_;

src/config/settings.h

@@ -130,6 +130,19 @@ public:
                                    muted_chat_cids_.end());
     }
 
+    // Hidden chat conversations (by cid) — hidden ones are filtered out of the list; a new incoming
+    // message un-hides them (you can't un-receive) so nothing is silently lost.
+    bool isChatHidden(const std::string& cid) const {
+        return std::find(hidden_chat_cids_.begin(), hidden_chat_cids_.end(), cid) != hidden_chat_cids_.end();
+    }
+    void setChatHidden(const std::string& cid, bool hidden) {
+        const bool already = isChatHidden(cid);
+        if (hidden && !already) hidden_chat_cids_.push_back(cid);
+        else if (!hidden && already)
+            hidden_chat_cids_.erase(std::remove(hidden_chat_cids_.begin(), hidden_chat_cids_.end(), cid),
+                                    hidden_chat_cids_.end());
+    }
+
     // Privacy
     bool getSaveZtxs() const { return save_ztxs_; }
     void setSaveZtxs(bool save) { save_ztxs_ = save; }
@@ -486,6 +499,7 @@ private:
     std::string skin_id_ = "dragonx";
     std::string chat_reply_zaddr_;
     std::vector<std::string> muted_chat_cids_;   // muted chat conversations by cid (Q10)
+    std::vector<std::string> hidden_chat_cids_;  // hidden chat conversations by cid
     bool save_ztxs_ = true;
     bool auto_shield_ = true;
     bool use_tor_ = false;

src/ui/windows/chat_tab.cpp

@@ -216,6 +216,7 @@ void RenderChatTab(App* app)
     // Build conversation summaries (single scan per conversation), sorted by most-recent activity.
     std::vector<ConvSummary> convs;
     for (const auto& cid : store.conversationIds()) {
+        if (app->settings() && app->settings()->isChatHidden(cid)) continue;  // hidden — a new message un-hides it
         const auto messages = store.conversation(cid);
         if (messages.empty()) continue;
         ConvSummary c;
@@ -439,6 +440,16 @@ void RenderChatTab(App* app)
                     app->settings()->setChatMuted(sel->cid, !muted);
                     app->settings()->save();
                 }
+                // Hide conversation — drops it from the list (messages stay in the encrypted store; a
+                // new incoming message brings it back). Deselect so the thread resets to the next one.
+                ImGui::SameLine();
+                if (ImGui::SmallButton(TR("chat_hide")) && app->settings()) {
+                    app->markChatConversationSeen(sel->cid, sel->lastTs);  // don't leave a phantom unread
+                    app->settings()->setChatHidden(sel->cid, true);
+                    app->settings()->save();
+                    s_selected_cid.clear();
+                    Notifications::instance().info(TR("chat_hidden_toast"));
+                }
             }
             ImGui::Separator();
 
@@ -620,6 +631,27 @@ void RenderChatTab(App* app)
         if (material::BeginOverlayDialog(ov)) {
             const float fieldW = ImGui::GetContentRegionAvail().x;
             material::LabeledInput(TR("chat_new_zaddr"), "##newz", s_new_zaddr, sizeof(s_new_zaddr), fieldW);
+            // Or pick from contacts — chat needs a shielded z-address, so only z-addr contacts are listed.
+            // Selecting one fills the field above (manual paste still works).
+            ImGui::SetNextItemWidth(fieldW);
+            if (ImGui::BeginCombo("##newzpick", TR("chat_pick_contact"), ImGuiComboFlags_HeightLarge)) {
+                int shown = 0;
+                for (const auto& e : book.entries()) {
+                    if (e.address.empty() || e.address[0] != 'z') continue;   // chat requires a z-address
+                    ++shown;
+                    const std::string item = e.label + "   " + shorten(e.address, 16, 8);
+                    if (ImGui::Selectable(item.c_str())) {
+                        std::strncpy(s_new_zaddr, e.address.c_str(), sizeof(s_new_zaddr) - 1);
+                        s_new_zaddr[sizeof(s_new_zaddr) - 1] = '\0';
+                    }
+                }
+                if (shown == 0) {
+                    ImGui::PushStyleColor(ImGuiCol_Text, material::OnSurfaceMedium());
+                    ImGui::TextUnformatted(TR("chat_no_z_contacts"));
+                    ImGui::PopStyleColor();
+                }
+                ImGui::EndCombo();
+            }
             ImGui::Dummy(ImVec2(0, Layout::spacingSm()));
             material::LabeledInput(TR("chat_new_message"), "##newm", s_new_msg, sizeof(s_new_msg), fieldW);
             ImGui::Dummy(ImVec2(0, Layout::spacingMd()));

src/util/i18n.cpp

@@ -252,6 +252,10 @@ void I18n::loadBuiltinEnglish()
         strings_["chat_len_over"] = "Message too long";
         strings_["chat_mute"] = "Mute";
         strings_["chat_unmute"] = "Unmute";
+        strings_["chat_hide"] = "Hide";
+        strings_["chat_hidden_toast"] = "Conversation hidden — a new message brings it back";
+        strings_["chat_pick_contact"] = "Choose from contacts\xE2\x80\xA6";
+        strings_["chat_no_z_contacts"] = "No shielded-address contacts yet";
         // Seed-phrase backup (full-node)
         strings_["seed_backup_button"] = "Seed phrase";
         strings_["tt_seed_backup"] = "Show and back up your wallet's 24-word recovery seed phrase";