feat: initial MQTT v5 debugging tool

- Tauri v2 + Vue 3 + TypeScript + Element Plus
- Connection management (CRUD + enable/disable/test)
- Preset system with {{variable}} placeholders
- Dashboard with live message scrolling + topic tree
- Payload inspector (JSON/Hex/Base64/Plain)
- Protocol-level logging (file + UI dual channel)
- Global variable manager with localStorage persistence
- MQTT v5 property support (user properties, content type, etc.)
- SubAck result tracking with subscribe_tracked API

src-tauri/Cargo.toml

@@ -0,0 +1,39 @@
+[package]
+name = "mqttx"
+version = "0.1.0"
+description = "A Tauri App"
+authors = ["you"]
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[package.metadata]
+# Tauri configuration metadata
+
+[lib]
+# The `_lib` suffix may seem redundant but it is necessary
+# to make the lib name unique and wouldn't conflict with the bin name.
+# This seems to be only an issue on Windows, see https://github.com/rust-lang/cargo/issues/8519
+name = "mqttx_lib"
+crate-type = ["staticlib", "cdylib", "rlib"]
+
+[build-dependencies]
+tauri-build = { version = "2", features = [] }
+
+[dependencies]
+tauri = { version = "2", features = [] }
+tauri-plugin-opener = "2"
+serde = { version = "1", features = ["derive"] }
+serde_json = "1"
+rumqttc-v5-next = "0.34"
+tokio = { version = "1", features = ["sync"] }
+uuid = { version = "1", features = ["v4"] }
+
+
+# Read the optimization guideline for more details: https://tauri.app/concept/size/#cargo-configuration
+[profile.release]
+codegen-units = 1
+lto = true
+opt-level = 3
+panic = "abort"
+strip = true