Comprehensive code quality and reliability improvements

- Fix panic-prone .unwrap() calls with proper error handling
- Fix SystemTime unwraps with safe fallback (unwrap_or(0))
- Fix infinite retry loop in client.rs with transport tracking
- Add exponential backoff for retries (100ms base, doubles each attempt)
- Forward MCP notifications instead of silently dropping them
- Add connection state tracking in multiplexing to avoid reconnecting
- Add graceful shutdown handling (SIGTERM/SIGINT) in stdio_proxy
- Mask bearer tokens in debug logs for security
- Secure OAuth token storage with 0600 file permissions
- Optimize Tokio features (specific vs "full") for smaller binary
- Use static OnceLock regex to avoid recompilation
- Support lowercase environment variables in config
- Remove panicking Default implementations
- Fix hardcoded response IDs to echo original request ID
- Pre-allocate vectors and reduce excessive cloning
- Store JoinHandle for spawned log task in server
- Add OAuth discovery with dynamic client registration

Author: dreygur

Cargo.lock

@@ -11,7 +11,7 @@ members = [
 resolver = "2"
 
 [workspace.dependencies]
-tokio = { version = "1.0", features = ["full"] }
+tokio = { version = "1.0", features = ["rt-multi-thread", "io-std", "io-util", "net", "sync", "time", "macros", "process", "signal"] }
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
 thiserror = "1.0"

Cargo.toml

@@ -21,3 +21,8 @@ oauth2 = { workspace = true }
 url = { workspace = true }
 uuid = { workspace = true }
 urlencoding = { workspace = true }
+sha2 = "0.10"
+rand = "0.8"
+open = "5.0"
+dirs = "5.0"
+md5 = "0.7"