feat: implement core functionality of ss-proxy server

- Implement HTTP/HTTPS and WebSocket dual-protocol proxy
- Add SQLite session management and database integration
- Support CLI arguments and environment variable configuration
- Add request routing, health check and other handlers
- Complete project documentation and translate code comments to English
- Configure Rust 1.90.0 toolchain

Signed-off-by: Xin Liu <[email protected]>

Author: apepkuss

.cargo/config.toml

@@ -0,0 +1,16 @@
+[build]
+incremental = true
+# jobs = 4
+
+[env]
+RUST_LOG = "info"
+
+[profile.dev]
+incremental = true
+opt-level = 0
+
+[profile.release]
+opt-level = 3
+lto = true
+strip = true
+codegen-units = 1