feat(desktop): embed BoosAPI Desktop client as a subproject

Vendor the rebranded BoosAPI Desktop client (Tauri + Vue) into metapi as
a monorepo subdirectory under desktop/. Source only — node_modules,
dist, Cargo target and the upstream .git history are excluded.

desktop/ keeps its own independent Cargo workspace (desktop/src-tauri
with crates/*); it is not part of the backend boosapi crate, so a
`cargo check` at the metapi root still compiles only the backend. Build
the desktop app from desktop/src-tauri per desktop/README.md.

Note: app icons are still placeholder assets pending the final BoosAPI
logo. The updater signing keys live outside the repo and are not
included.

desktop/src-tauri/crates/open-agent-sdk/Cargo.toml

@@ -0,0 +1,78 @@
+[package]
+name = "open-agent-sdk"
+version = "0.1.0"
+edition = "2021"
+description = "Open Agent SDK - A Rust framework for building autonomous AI agents"
+license = "MIT"
+repository = "https://github.com/codeany-ai/open-agent-sdk-rust"
+
+[dependencies]
+tokio = { version = "1", features = ["full"] }
+tokio-stream = "0.1"
+futures = "0.3"
+reqwest = { version = "0.12", features = ["json", "stream"] }
+serde = { version = "1", features = ["derive"] }
+serde_json = "1"
+uuid = { version = "1", features = ["v4"] }
+glob = "0.3"
+regex = "1"
+chrono = "0.4"
+async-trait = "0.1"
+thiserror = "2"
+bytes = "1"
+pin-project-lite = "0.2"
+tracing = "0.1"
+base64 = "0.22"
+tokio-util = "0.7"
+serde_yaml = "0.9"
+
+[target.'cfg(target_os = "windows")'.dependencies]
+windows-sys = { version = "0.59", features = ["Win32_System_Threading"] }
+
+[dev-dependencies]
+tokio = { version = "1", features = ["full", "test-util"] }
+tempfile = "3"
+
+[[example]]
+name = "01-simple-query"
+path = "examples/01-simple-query.rs"
+
+[[example]]
+name = "02-multi-tool"
+path = "examples/02-multi-tool.rs"
+
+[[example]]
+name = "03-multi-turn"
+path = "examples/03-multi-turn.rs"
+
+[[example]]
+name = "04-prompt-api"
+path = "examples/04-prompt-api.rs"
+
+[[example]]
+name = "05-custom-system-prompt"
+path = "examples/05-custom-system-prompt.rs"
+
+[[example]]
+name = "06-mcp-server"
+path = "examples/06-mcp-server.rs"
+
+[[example]]
+name = "07-custom-tools"
+path = "examples/07-custom-tools.rs"
+
+[[example]]
+name = "08-oneshot-query"
+path = "examples/08-oneshot-query.rs"
+
+[[example]]
+name = "09-subagents"
+path = "examples/09-subagents.rs"
+
+[[example]]
+name = "10-permissions"
+path = "examples/10-permissions.rs"
+
+[[example]]
+name = "web-chat"
+path = "examples/web/main.rs"