feat: 将 Android flomo-ai 移植为 Rust Windows 桌面应用

- 使用 egui + eframe 构建跨平台 GUI
- 实现 LLM API 调用（OpenAI 兼容格式）
- 实现提示词管理（添加/删除/选择）
- 实现快速操作按钮（错别字检查、总结、翻译、润色）
- 实现明暗主题切换
- 实现 JSON 配置持久化
- 实现剪贴板复制功能
- MinGW 工具链编译，无控制台窗口

Cargo.toml

@@ -0,0 +1,25 @@
+[package]
+name = "flomo-ai-desktop"
+version = "0.1.0"
+edition = "2021"
+
+[[bin]]
+name = "flomo-ai"
+path = "src/main.rs"
+
+[dependencies]
+egui = "0.29"
+eframe = { version = "0.29", default-features = false, features = ["default_fonts", "glow"] }
+serde = { version = "1", features = ["derive"] }
+serde_json = "1"
+reqwest = { version = "0.12", default-features = false, features = ["blocking", "json", "rustls-tls"] }
+dirs = "5"
+clipboard-win = "5"
+arboard = "3"
+
+[profile.release]
+opt-level = "z"
+lto = true
+codegen-units = 1
+panic = "abort"
+strip = true