feat(v3): migrate workspace to API, Tauri desktop, and v3 crates; remove legacy MCP stack

- Add apps/api, desktop Tauri shell, domain/application/crypto/device-auth/infrastructure-db
- Replace desktop-daemon vault integration; drop secrets-core and secrets-mcp*
- Ignore apps/desktop/dist and generated Tauri icons; document icon/dist steps in AGENTS.md
- Apply rustfmt; fix clippy (collapsible_if, HTTP method as str)

Cargo.toml

@@ -1,8 +1,14 @@
 [workspace]
 members = [
-    "crates/secrets-core",
-    "crates/secrets-mcp",
-    "crates/secrets-mcp-local",
+    "apps/api",
+    "apps/desktop/src-tauri",
+    "crates/application",
+    "crates/client-integrations",
+    "crates/crypto",
+    "crates/desktop-daemon",
+    "crates/device-auth",
+    "crates/domain",
+    "crates/infrastructure-db",
 ]
 resolver = "2"
 
@@ -14,7 +20,7 @@ edition = "2024"
 tokio = { version = "^1.50.0", features = ["rt-multi-thread", "macros", "fs", "io-util", "process", "signal"] }
 
 # Database
-sqlx = { version = "^0.8.6", features = ["runtime-tokio", "tls-rustls", "postgres", "uuid", "json", "chrono"] }
+sqlx = { version = "^0.8.6", features = ["runtime-tokio", "tls-rustls", "postgres", "sqlite", "uuid", "json", "chrono"] }
 
 # Serialization
 serde = { version = "^1.0.228", features = ["derive"] }
@@ -26,12 +32,13 @@ toml = "^1.0.7"
 aes-gcm = "^0.10.3"
 sha2 = "^0.10.9"
 rand = "^0.10.0"
+hex = "0.4"
 
 # Utils
 anyhow = "^1.0.102"
 thiserror = "^2"
 chrono = { version = "^0.4.44", features = ["serde"] }
-uuid = { version = "^1.22.0", features = ["serde"] }
+uuid = { version = "^1.22.0", features = ["serde", "v4"] }
 tracing = "^0.1"
 tracing-subscriber = { version = "^0.3", features = ["env-filter"] }
 dotenvy = "^0.15"
@@ -39,3 +46,9 @@ dotenvy = "^0.15"
 # HTTP
 # system-proxy：与浏览器一致，读取 macOS/Windows 系统代理（禁用 default 后须显式开启，否则 OAuth 出站不走 Clash 等）
 reqwest = { version = "^0.12", default-features = false, features = ["rustls-tls", "json", "system-proxy"] }
+axum = "0.8"
+http = "1"
+url = "2"
+rmcp = { version = "1", features = ["server", "macros", "transport-streamable-http-server", "schemars"] }
+tauri = { version = "2", features = [] }
+tauri-build = { version = "2", features = [] }