diff --git a/docs/modernization/debt.md b/docs/modernization/debt.md
index f8e7ce72..776124fd 100644
--- a/docs/modernization/debt.md
+++ b/docs/modernization/debt.md
@@ -18,6 +18,28 @@ agent or engineer to remove them without reconstructing context from chat.
 
 ## Reductions
 
+- 2026-06-17: `DEBT-0039` was narrowed again. `App::dialog_browse()` in
+  `src/app_dialogs_workflow.cpp` now delegates retained browse-dialog button
+  wiring and selected-path open execution through
+  `src/legacy_document_open_services.*`, so the app dialog shell no longer
+  owns that document-open handoff inline while retained dialog creation,
+  unsaved-project prompting, project-open execution, and title/layer refresh
+  still remain.
+- 2026-06-17: `DEBT-0038` was narrowed again. The retained cloud upload and
+  download background execution in `src/legacy_cloud_services.cpp` now routes
+  through `AppRuntime::canvas_async_task` instead of a file-static worker
+  singleton, while retained prompt/progress lifetime, OpenGL context guards,
+  thumbnail loading, and transfer execution still remain in the cloud bridge.
+- 2026-06-17: `DEBT-0048` was narrowed again. The retained ABR/PPBR import path
+  in `src/legacy_brush_package_import_services.cpp` now uses
+  `AppRuntime::canvas_async_task` instead of a file-static worker singleton,
+  while the legacy preset panel remains the importer/storage owner and broader
+  brush asset/UI ownership transfer still remains open.
+- 2026-06-17: `DEBT-0044` was narrowed again. The retained asynchronous
+  timelapse export path in `src/legacy_document_export_services.cpp` now routes
+  through `AppRuntime::canvas_async_task` instead of a file-static worker
+  singleton, while retained `App::rec_export`, animation MP4 execution, and
+  mobile/Web completion paths still remain in the video-export bridge.
 - 2026-06-17: `DEBT-0036` was narrowed again. `src/canvas_layer.cpp` now
   routes retained `Layer` / `LayerFrame` render queueing through
   `src/renderer_gl/render_runtime_dispatch.h` instead of direct
diff --git a/docs/modernization/roadmap.md b/docs/modernization/roadmap.md
index 7c9255e2..8d8789d6 100644
--- a/docs/modernization/roadmap.md
+++ b/docs/modernization/roadmap.md
@@ -79,6 +79,10 @@ Current conclusion:
 - `AppRuntime` now owns synchronized running flags and explicit
   same-thread/post-reject queue behavior, but broader app/runtime singleton
   reach and retained shell ownership still remain.
+- The document-browse dialog handoff now lives in
+  `src/legacy_document_open_services.*`, and retained cloud upload/download,
+  brush-package import, and timelapse-export async paths now use
+  `AppRuntime::canvas_async_task` instead of file-static worker singletons.
 - Platform extraction improved substantially and the root app source group no
   longer compiles Web platform sources directly, but broader CMake and
   entrypoint cleanup are not complete.
diff --git a/docs/modernization/tasks.md b/docs/modernization/tasks.md
index aad5b2b9..c16c8544 100644
--- a/docs/modernization/tasks.md
+++ b/docs/modernization/tasks.md
@@ -59,6 +59,12 @@ Key facts:
 - `AppRuntime` now owns synchronized running flags plus explicit post/reject,
   same-thread execution, and queue-drain behavior, but broader singleton reach
   and app-shell ownership remain.
+- Retained cloud upload/download, brush-package import, and timelapse-export
+  async paths now route through `AppRuntime::canvas_async_task`, but dialog and
+  execution ownership still remains in retained app/document/cloud bridges.
+- `App::dialog_browse()` no longer owns browse-dialog button wiring inline; the
+  retained document-open bridge now owns that handoff in
+  `src/legacy_document_open_services.*`.
 
 ## Parallel Assignment Rules
 
diff --git a/src/app_dialogs_workflow.cpp b/src/app_dialogs_workflow.cpp
index 5f87ffe5..0ce9c496 100644
--- a/src/app_dialogs_workflow.cpp
+++ b/src/app_dialogs_workflow.cpp
@@ -1,6 +1,7 @@
 #include "pch.h"
 #include "app.h"
 #include "app_core/document_resize.h"
+#include "legacy_document_open_services.h"
 #include "legacy_document_canvas_services.h"
 #include "legacy_document_session_services.h"
 #include "legacy_ui_overlay_services.h"
@@ -10,32 +11,6 @@
 
 namespace {
 
-void wire_document_browse_dialog_actions(
-    App& app,
-    const std::shared_ptr<NodeDialogBrowse>& dialog,
-    Node& overlay_anchor,
-    pp::ui::NodeHandle overlay_handle)
-{
-    const auto close_dialog = [&overlay_anchor, overlay_handle]() {
-        const auto close_status =
-            pp::panopainter::close_legacy_overlay_node(overlay_anchor, overlay_handle);
-        (void)close_status;
-    };
-
-    dialog->btn_ok->on_click = [&app, dialog, close_dialog](Node*)
-    {
-        if (dialog->is_selected())
-        {
-            app.open_document(dialog->selected_path);
-            close_dialog();
-        }
-    };
-    dialog->btn_cancel->on_click = [close_dialog](Node*)
-    {
-        close_dialog();
-    };
-}
-
 void wire_document_save_dialog_buttons(
     App& app,
     const std::shared_ptr<NodeDialogSave>& dialog,
@@ -201,7 +176,11 @@ void App::dialog_browse()
             return;
         }
         const auto overlay_handle = overlay.value();
-        wire_document_browse_dialog_actions(*this, dialog, *overlay_anchor, overlay_handle);
+        pp::panopainter::wire_legacy_document_browse_dialog_actions(
+            *this,
+            dialog,
+            *overlay_anchor,
+            overlay_handle);
     };
 
     continue_document_workflow_after_optional_save(show_dialog);
diff --git a/src/legacy_brush_package_import_services.cpp b/src/legacy_brush_package_import_services.cpp
index afcdf600..86f487d3 100644
--- a/src/legacy_brush_package_import_services.cpp
+++ b/src/legacy_brush_package_import_services.cpp
@@ -5,88 +5,32 @@
 #include "app.h"
 #include "node_panel_brush.h"
 
-#include <condition_variable>
-#include <deque>
 #include <functional>
 #include <string>
-#include <mutex>
-#include <stop_token>
-#include <thread>
 
 namespace pp::panopainter {
 namespace {
 
-class LegacyBrushPackageWorker final {
-public:
-    LegacyBrushPackageWorker()
-        : worker_([this](std::stop_token stop_token) {
-            run(stop_token);
-        })
-    {
-    }
-
-    ~LegacyBrushPackageWorker()
-    {
-        shutdown();
-    }
-
-    void post(std::function<void()> task)
-    {
-        {
-            std::lock_guard<std::mutex> lock(mutex_);
-            if (stopping_)
-                return;
-            tasks_.push_back(std::move(task));
-        }
-        cv_.notify_one();
-    }
-
-private:
-    void shutdown()
-    {
-        {
-            std::lock_guard<std::mutex> lock(mutex_);
-            stopping_ = true;
-        }
-        cv_.notify_all();
-    }
-
-    void run(std::stop_token stop_token)
-    {
-        for (;;) {
-            std::function<void()> task;
-            {
-                std::unique_lock<std::mutex> lock(mutex_);
-                cv_.wait(lock, [&] {
-                    return stopping_ || stop_token.stop_requested() || !tasks_.empty();
-                });
-                if ((stopping_ || stop_token.stop_requested()) && tasks_.empty())
-                    break;
-                task = std::move(tasks_.front());
-                tasks_.pop_front();
-            }
-
-            if (task) {
-                try {
-                    task();
-                } catch (...) {
-                    LOG("brush package import worker task failed");
-                }
-            }
-        }
-    }
-
-    std::mutex mutex_;
-    std::condition_variable cv_;
-    std::deque<std::function<void()>> tasks_;
-    bool stopping_ = false;
-    std::jthread worker_;
-};
-
-LegacyBrushPackageWorker& brush_package_worker()
+void queue_legacy_brush_package_import_job(
+    App& app,
+    std::shared_ptr<NodePanelBrushPreset> presets,
+    pp::app::BrushPackageImportKind kind,
+    std::string path_string)
 {
-    static LegacyBrushPackageWorker worker;
-    return worker;
+    app.runtime().canvas_async_task([presets = std::move(presets),
+                                     kind,
+                                     path_string = std::move(path_string)]() mutable {
+        BT_SetTerminate();
+        if (!presets) {
+            return;
+        }
+        if (kind == pp::app::BrushPackageImportKind::abr) {
+            presets->import_abr(path_string);
+            return;
+        }
+
+        presets->import_ppbr(path_string);
+    });
 }
 
 class LegacyBrushPackageImportServices final : public pp::app::BrushPackageImportServices {
@@ -98,20 +42,8 @@ public:
 
     void import_brush_package(pp::app::BrushPackageImportKind kind, std::string_view path) override
     {
-        auto presets = app_.presets;
         const auto path_string = std::string(path);
-        brush_package_worker().post([presets, kind, path_string] {
-            BT_SetTerminate();
-            if (!presets) {
-                return;
-            }
-            if (kind == pp::app::BrushPackageImportKind::abr) {
-                presets->import_abr(path_string);
-                return;
-            }
-
-            presets->import_ppbr(path_string);
-        });
+        queue_legacy_brush_package_import_job(app_, app_.presets, kind, std::move(path_string));
     }
 
 private:
diff --git a/src/legacy_cloud_services.cpp b/src/legacy_cloud_services.cpp
index 0c5cfe17..44a4b3d3 100644
--- a/src/legacy_cloud_services.cpp
+++ b/src/legacy_cloud_services.cpp
@@ -21,79 +21,6 @@ pp::foundation::Status execute_legacy_cloud_download_selection_action(
 
 namespace {
 
-class LegacyCloudWorker final {
-public:
-    LegacyCloudWorker()
-        : worker_([this](std::stop_token stop_token) {
-            run(stop_token);
-        })
-    {
-    }
-
-    ~LegacyCloudWorker()
-    {
-        shutdown();
-    }
-
-    void post(std::function<void()> task)
-    {
-        {
-            std::lock_guard<std::mutex> lock(mutex_);
-            if (stopping_)
-                return;
-            tasks_.push_back(std::move(task));
-        }
-        cv_.notify_one();
-    }
-
-private:
-    void shutdown()
-    {
-        {
-            std::lock_guard<std::mutex> lock(mutex_);
-            stopping_ = true;
-        }
-        cv_.notify_all();
-    }
-
-    void run(std::stop_token stop_token)
-    {
-        for (;;) {
-            std::function<void()> task;
-            {
-                std::unique_lock<std::mutex> lock(mutex_);
-                cv_.wait(lock, [&] {
-                    return stopping_ || stop_token.stop_requested() || !tasks_.empty();
-                });
-                if ((stopping_ || stop_token.stop_requested()) && tasks_.empty())
-                    break;
-                task = std::move(tasks_.front());
-                tasks_.pop_front();
-            }
-
-            if (task) {
-                try {
-                    task();
-                } catch (...) {
-                    LOG("cloud worker task failed");
-                }
-            }
-        }
-    }
-
-    std::mutex mutex_;
-    std::condition_variable cv_;
-    std::deque<std::function<void()>> tasks_;
-    bool stopping_ = false;
-    std::jthread worker_;
-};
-
-LegacyCloudWorker& cloud_worker()
-{
-    static LegacyCloudWorker worker;
-    return worker;
-}
-
 #if WITH_CURL
 int progress_callback_download(void* clientp, curl_off_t dltotal,
     curl_off_t dlnow, curl_off_t ultotal, curl_off_t ulnow)
@@ -330,7 +257,7 @@ void setup_cloud_publish_prompt(App& app, bool save_before_upload)
     const auto prompt_plan = pp::app::plan_cloud_publish_prompt();
     auto dialog = app.message_box(prompt_plan.title, prompt_plan.message, prompt_plan.show_cancel);
     wire_cloud_publish_prompt_buttons(dialog, [&app, save_before_upload] {
-        queue_legacy_cloud_worker_task([app = &app, save_before_upload] {
+        app.runtime().canvas_async_task([app = &app, save_before_upload] {
             execute_cloud_publish_worker(*app, save_before_upload);
         });
     });
@@ -438,7 +365,7 @@ public:
 
     void start_download(const pp::app::CloudDownloadRequest& request) override
     {
-        queue_legacy_cloud_worker_task([app = &app_, request] {
+        app_.runtime().canvas_async_task([app = &app_, request] {
             execute_cloud_download_thread(*app, request);
         });
     }
@@ -458,7 +385,11 @@ void show_cloud_save_required_warning(App& app)
 
 void queue_legacy_cloud_worker_task(std::function<void()> task)
 {
-    cloud_worker().post(std::move(task));
+    if (App::I == nullptr) {
+        LOG("cloud worker task skipped: app unavailable");
+        return;
+    }
+    App::I->runtime().canvas_async_task(std::move(task));
 }
 
 pp::foundation::Status execute_legacy_cloud_upload_plan(
diff --git a/src/legacy_document_export_services.cpp b/src/legacy_document_export_services.cpp
index f3a541dc..c4b9b70e 100644
--- a/src/legacy_document_export_services.cpp
+++ b/src/legacy_document_export_services.cpp
@@ -8,16 +8,11 @@
 #include "paint_renderer/compositor.h"
 
 #include <array>
-#include <condition_variable>
 #include <fstream>
-#include <deque>
 #include <functional>
-#include <mutex>
 #include <limits>
 #include <span>
 #include <string>
-#include <stop_token>
-#include <thread>
 
 namespace pp::panopainter {
 namespace {
@@ -36,79 +31,6 @@ struct LegacyDocumentExportSnapshotReports {
     pp::paint_renderer::DocumentFrameFacePngExportResult face_pngs;
 };
 
-class LegacyDocumentVideoExportWorker final {
-public:
-    LegacyDocumentVideoExportWorker()
-        : worker_([this](std::stop_token stop_token) {
-            run(stop_token);
-        })
-    {
-    }
-
-    ~LegacyDocumentVideoExportWorker()
-    {
-        shutdown();
-    }
-
-    void post(std::function<void()> task)
-    {
-        {
-            std::lock_guard<std::mutex> lock(mutex_);
-            if (stopping_)
-                return;
-            tasks_.push_back(std::move(task));
-        }
-        cv_.notify_one();
-    }
-
-private:
-    void shutdown()
-    {
-        {
-            std::lock_guard<std::mutex> lock(mutex_);
-            stopping_ = true;
-        }
-        cv_.notify_all();
-    }
-
-    void run(std::stop_token stop_token)
-    {
-        for (;;) {
-            std::function<void()> task;
-            {
-                std::unique_lock<std::mutex> lock(mutex_);
-                cv_.wait(lock, [&] {
-                    return stopping_ || stop_token.stop_requested() || !tasks_.empty();
-                });
-                if ((stopping_ || stop_token.stop_requested()) && tasks_.empty())
-                    break;
-                task = std::move(tasks_.front());
-                tasks_.pop_front();
-            }
-
-            if (task) {
-                try {
-                    task();
-                } catch (...) {
-                    LOG("document video export worker task failed");
-                }
-            }
-        }
-    }
-
-    std::mutex mutex_;
-    std::condition_variable cv_;
-    std::deque<std::function<void()>> tasks_;
-    bool stopping_ = false;
-    std::jthread worker_;
-};
-
-LegacyDocumentVideoExportWorker& document_video_export_worker()
-{
-    static LegacyDocumentVideoExportWorker worker;
-    return worker;
-}
-
 pp::foundation::Status write_export_binary_file(std::string_view path, std::span<const std::byte> bytes)
 {
     if (path.empty()) {
@@ -846,7 +768,7 @@ public:
         auto* app = &app_;
         auto path_string = std::string(path);
         if (asynchronous_) {
-            document_video_export_worker().post([app, path_string = std::move(path_string)]() mutable {
+            app_.runtime().canvas_async_task([app, path_string = std::move(path_string)]() mutable {
                 BT_SetTerminate();
                 app->rec_export(path_string);
                 app->ui_task([app, path_string = std::move(path_string)]() mutable {
diff --git a/src/legacy_document_open_services.cpp b/src/legacy_document_open_services.cpp
index 85594c7e..0a4888ba 100644
--- a/src/legacy_document_open_services.cpp
+++ b/src/legacy_document_open_services.cpp
@@ -9,6 +9,7 @@
 #include "legacy_history_services.h"
 #include "legacy_ui_overlay_services.h"
 #include "log.h"
+#include "node_dialog_browse.h"
 #include "node_panel_brush.h"
 #include "node_panel_layer.h"
 
@@ -154,6 +155,32 @@ private:
 
 } // namespace
 
+void wire_legacy_document_browse_dialog_actions(
+    App& app,
+    const std::shared_ptr<NodeDialogBrowse>& dialog,
+    Node& overlay_anchor,
+    pp::ui::NodeHandle overlay_handle)
+{
+    const auto close_dialog = [&overlay_anchor, overlay_handle]() {
+        const auto close_status =
+            pp::panopainter::close_legacy_overlay_node(overlay_anchor, overlay_handle);
+        (void)close_status;
+    };
+
+    dialog->btn_ok->on_click = [&app, dialog, close_dialog](Node*)
+    {
+        if (dialog->is_selected())
+        {
+            app.open_document(dialog->selected_path);
+            close_dialog();
+        }
+    };
+    dialog->btn_cancel->on_click = [close_dialog](Node*)
+    {
+        close_dialog();
+    };
+}
+
 pp::foundation::Status execute_legacy_document_open_plan(
     App& app,
     pp::app::DocumentOpenPlanAction action,
diff --git a/src/legacy_document_open_services.h b/src/legacy_document_open_services.h
index 88f1674e..6f0fc5d9 100644
--- a/src/legacy_document_open_services.h
+++ b/src/legacy_document_open_services.h
@@ -2,11 +2,15 @@
 
 #include "app_core/document_session.h"
 #include "foundation/result.h"
+#include "ui_core/overlay_lifetime.h"
 
 #include <string>
 #include <string_view>
+#include <memory>
 
 class App;
+class Node;
+class NodeDialogBrowse;
 
 namespace pp::panopainter {
 
@@ -19,6 +23,12 @@ namespace pp::panopainter {
     pp::app::DocumentOpenPlanAction action,
     const pp::app::DocumentOpenRoute& route);
 
+void wire_legacy_document_browse_dialog_actions(
+    App& app,
+    const std::shared_ptr<NodeDialogBrowse>& dialog,
+    Node& overlay_anchor,
+    pp::ui::NodeHandle overlay_handle);
+
 void execute_legacy_downloaded_project_open(
     App& app,
     std::string_view path,