feat: replace Tauri with iced for native cross-platform GUI

- Create iced-app crate with pure Rust GUI using iced 0.13
- Implement server list, connect form, channel/user panels, messaging
- Implement ServerQuery panel for direct server queries
- Add VoiceEngine in tsaudio for decode/buffer/playback pipeline
- Update CI to build iced binary (no frontend build step needed)
- Remove Tauri dependency from workspace
- 69 tests passing across all crates

src/iced-app/Cargo.toml

@@ -0,0 +1,27 @@
+[package]
+name = "re-teamspeak"
+version = "1.0.0"
+edition = "2021"
+license = "MIT OR Apache-2.0"
+description = "TeamSpeak 3 client built with iced"
+
+[[bin]]
+name = "re-teamspeak"
+path = "src/main.rs"
+
+[dependencies]
+iced = { version = "0.13", features = ["tokio", "debug"] }
+tokio = { workspace = true }
+serde = { workspace = true }
+serde_json = { workspace = true }
+tracing = { workspace = true }
+tracing-subscriber = { workspace = true }
+chrono = { workspace = true }
+
+shared = { workspace = true }
+tscore = { workspace = true }
+tsaudio = { workspace = true }
+tsdb = { workspace = true }
+
+[features]
+default = []