feat(app): 初始化本地通知桌面应用

搭建 .NET 8 WPF 应用骨架，加入系统托盘、单实例启动与主控制面板。
实现本地 HTTP /notify 消息接入、频道严格匹配、免打扰、熔断限流与历史持久化。
补充弹窗样式配置、队列/推挤/替换展示、溢出处理、应用图标和项目文档。

Initial-Commit: true

README.md

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+# Omni-Notify
+
+Omni-Notify is a Windows 10+ WPF desktop app for receiving local structured messages and showing configurable, non-interactive visual popups.
+
+## Tech Stack
+
+- .NET 8 WPF for the desktop UI and popup windows
+- Windows Forms `NotifyIcon` for the system tray entry
+- Built-in `HttpListener` for local message intake
+- JSON persistence under `%LOCALAPPDATA%\OmniNotify\state.json`
+
+## Local Message API
+
+When the app is running, it listens by default on:
+
+```text
+http://127.0.0.1:19845/notify
+```
+
+Send a POST request with UTF-8 JSON:
+
+```json
+{
+  "channel": "default",
+  "title": "Build finished",
+  "body": "The nightly job completed successfully."
+}
+```
+
+Channels must be created in the control panel first. Unknown channels are blocked and recorded in history as `IllegalChannel`.
+
+## Build
+
+```powershell
+dotnet build
+```