feat(brand): add application logo for exe and window icon

新增品牌标识并接入运行时与打包流程。

- `scripts/gen_logo.py` 从单一几何定义同时产出 SVG 母版、多尺寸 ICO 和
  PNG 预览，避免母版与位图漂移；改样式改脚本后重新生成即可。
- 标记为暖橙圆角徽章 + 白色上升箭头（提升并发布）+ 四角星芒（AI 生成），
  刻意避开蝦皮官方购物袋标识，避免暗示官方关联。
- ICO 含 16/20/24/32/40/48/64/128/256 九档，每档从矢量几何独立渲染而非
  由大图缩放，保证任务栏与资源管理器小尺寸清晰。
- `app/assets` 作为可导入包提供无 Qt 依赖的路径解析，兼容源码树、
  PyInstaller onedir 的 _MEIPASS 与 exe 同级目录三种布局。
- `widgets.app_icon()` 在 Qt 缺失或资源未生成时返回 None，调用方容错；
  在 QApplication 上设置图标以便任务栏、对话框和消息框一并继承，
  MainWindow 另行设置以覆盖直接构造窗口的测试路径。
- 两个 spec 均加 `icon=`，主 spec 收集资源到 datas 并在资源缺失时直接
  报错提示先跑生成脚本。

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

app/assets/__init__.py

@@ -0,0 +1,57 @@
+"""Bundled static assets (application icon).
+
+The icon ships inside the package so the same file backs the window icon at
+runtime and the executable icon at build time. Keep this module free of Qt
+imports: the packaging spec imports it while collecting data files.
+
+Regenerate the files with ``py -3.10 scripts/gen_logo.py``.
+"""
+
+from __future__ import annotations
+
+import os
+import sys
+
+ICON_NAME = "cmshopee.ico"
+ICON_PNG_NAME = "cmshopee-256.png"
+
+_PACKAGE_DIR = os.path.dirname(os.path.abspath(__file__))
+
+
+def _candidate_paths(name):
+    """Locations to probe, covering source tree and PyInstaller onedir."""
+
+    yield os.path.join(_PACKAGE_DIR, name)
+
+    bundle_dir = getattr(sys, "_MEIPASS", None)
+    if bundle_dir:
+        yield os.path.join(bundle_dir, "app", "assets", name)
+
+    if getattr(sys, "frozen", False):
+        yield os.path.join(
+            os.path.dirname(os.path.abspath(sys.executable)),
+            "app",
+            "assets",
+            name,
+        )
+
+
+def asset_path(name):
+    """Return an existing asset path, or None when it is not bundled."""
+
+    for candidate in _candidate_paths(name):
+        if candidate and os.path.isfile(candidate):
+            return candidate
+    return None
+
+
+def icon_path():
+    """Path to the multi-size Windows icon, or None when unavailable."""
+
+    return asset_path(ICON_NAME)
+
+
+def icon_png_path():
+    """Path to the 256px PNG fallback, or None when unavailable."""
+
+    return asset_path(ICON_PNG_NAME)

app/assets/cmshopee-logo.svg

@@ -0,0 +1,14 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 256" width="256" height="256" role="img" aria-label="蝦皮圈優化助手">
+  <title>蝦皮圈優化助手</title>
+  <defs>
+    <linearGradient id="badge" x1="0" y1="0" x2="1" y2="1">
+      <stop offset="0" stop-color="#F5793F"/>
+      <stop offset="1" stop-color="#D6371C"/>
+    </linearGradient>
+  </defs>
+  <rect x="10" y="10" width="236" height="236" rx="54" fill="url(#badge)"/>
+  <path d="M 112 58 L 56 116 L 168 116 Z" fill="#FFFFFF"/>
+  <rect x="90" y="110" width="44" height="52" rx="10" fill="#FFFFFF"/>
+  <rect x="56" y="178" width="112" height="26" rx="13" fill="#FFFFFF"/>
+  <polygon points="194.0,40.0 201.8,66.2 228.0,74.0 201.8,81.8 194.0,108.0 186.2,81.8 160.0,74.0 186.2,66.2" fill="#FFFFFF"/>
+</svg>

app/gui/__init__.py

@@ -122,6 +122,11 @@ def main() -> int:
         return 1
     _ensure_offscreen_for_headless_tests()
     app = QApplication.instance() or QApplication(sys.argv)
+    # Set on the application so the taskbar button, dialogs and message boxes
+    # all inherit it, not just the main window.
+    startup_icon = app_icon()
+    if startup_icon is not None:
+        app.setWindowIcon(startup_icon)
     health_context = update_health.context_from_argv(
         sys.argv,
         appconfig.app_base_dir(),

app/gui/main_window.py

@@ -98,6 +98,9 @@ class MainWindow(QMainWindow):
             or appconfig.ai_models_config_path(self.config)
         )
         self.setWindowTitle(display_name())
+        window_icon = app_icon()
+        if window_icon is not None:
+            self.setWindowIcon(window_icon)
         _fit_and_center_window(self)
         self.setStyleSheet(BUTTON_BASE_STYLE)
         self._settings_tab_index = TAB_TITLES.index("设置")

app/gui/widgets.py

@@ -8,6 +8,8 @@ import threading
 import time
 from concurrent.futures import ThreadPoolExecutor, as_completed
 
+from .. import assets
+
 try:
     from PySide6.QtCore import QAbstractTableModel, QModelIndex, Qt, QTimer
     from PySide6.QtGui import QColor, QIcon, QImage, QPainter, QPixmap
@@ -136,6 +138,22 @@ QPushButton:disabled {{
 _RawQMessageBox = QMessageBox if QT_IMPORT_ERROR is None else None
 
 
+def app_icon():
+    """Application icon, or None when Qt is unavailable or the file is missing.
+
+    Callers must tolerate None: the icon is a packaged asset, and a source
+    checkout that has not run scripts/gen_logo.py still has to start.
+    """
+
+    if QT_IMPORT_ERROR is not None:
+        return None
+    path = assets.icon_path() or assets.icon_png_path()
+    if not path:
+        return None
+    icon = QIcon(path)
+    return None if icon.isNull() else icon
+
+
 class _GuiAttributeProxy:
     def __init__(self, name, fallback):
         self._name = name