feat(marathonctl): Add CLI arguments for multi-instance support

Added --db-path and --control-socket arguments to app binary to enable
running multiple instances simultaneously.

Updated marathonctl to use clap with --socket argument for targeting
different instances.

Enables multi-client testing with isolated databases and control sockets.

Refs #131, #132

Signed-off-by: Sienna Meridian Satterwhite <sienna@r3t.io>

crates/app/Cargo.toml

@@ -34,6 +34,7 @@ futures-lite = "2.0"
 rkyv = { workspace = true }
 bytes = "1.0"
 crossbeam-channel = "0.5.15"
+clap = { version = "4.0", features = ["derive"] }
 
 [target.'cfg(target_os = "ios")'.dependencies]
 objc = "0.2"