FRE-606: Add Tauri desktop framework with cross-platform support

- Configure Tauri v2 for macOS, Windows, Linux
- Implement native menu bar (File, Edit, View, Window, Help)
- Add system tray with show/hide/quit functionality
- Create auto-updater framework with periodic checks
- Set up window state persistence
- Configure plugins (fs, http, dialog, shell, store)
- Add build scripts for all platforms
- Include comprehensive documentation

Files:
- src-tauri/Cargo.toml
- src-tauri/tauri.conf.json
- src-tauri/build.rs
- src-tauri/src/main.rs
- src-tauri/src/lib.rs
- src-tauri/src/menu.rs
- src-tauri/src/tray.rs
- src-tauri/src/updater.rs
- src-tauri/Cargo.lock
- src-tauri/icons/tray-icon.svg
- src-tauri/tauri.build.conf
- src-tauri/README.md
- .gitignore
- package.json (Tauri CLI scripts)

src-tauri/Cargo.toml

@@ -0,0 +1,47 @@
+[package]
+name = "frenocorp-desktop"
+version = "0.1.0"
+description = "FrenoCorp Desktop Application"
+authors = ["FrenoCorp"]
+edition = "2021"
+
+[lib]
+name = "frenocorp_lib"
+crate-type = ["lib", "cdylib", "staticlib"]
+
+[[bin]]
+name = "frenocorp"
+path = "src/main.rs"
+
+[dependencies]
+serde = { version = "1.0", features = ["derive"] }
+serde_json = "1.0"
+tauri = { version = "2", features = ["tray-icon", "macos-private-api"] }
+tauri-plugin-fs = "2"
+tauri-plugin-http = "2"
+tauri-plugin-dialog = "2"
+tauri-plugin-shell = "2"
+tauri-plugin-store = "2"
+tokio = { version = "1.35", features = ["full"] }
+thiserror = "1.0"
+log = "0.4"
+env_logger = "0.10"
+
+[target.'cfg(windows)'.dependencies]
+windows = { version = "0.52", features = ["Win32_UI_Shell"] }
+
+[target.'cfg(target_os = "macos")'.dependencies]
+cocoa = "0.25"
+
+[target.'cfg(target_os = "linux")'.dependencies]
+gtk = "0.18"
+
+[build-dependencies]
+tauri-build = { version = "2", features = [] }
+
+[profile.release]
+panic = "abort"
+codegen-units = 1
+lto = true
+opt-level = "s"
+strip = true