feat(cli): enhance duration parsing with humantime

Allow fractional and composite duration inputs for `--duration` and `--interval` options.

Cargo.lock

@@ -778,6 +778,12 @@ dependencies = [
  "digest 0.11.3",
 ]
 
+[[package]]
+name = "humantime"
+version = "2.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "15cdd26707701c53297e2fa6afb323d55fbc1d0810c3aec078ae3ef0424c3c15"
+
 [[package]]
 name = "hybrid-array"
 version = "0.4.15"
@@ -893,6 +899,7 @@ dependencies = [
  "ctrlc",
  "futures-core",
  "hex",
+ "humantime",
  "irtt-client",
  "irtt-proto",
  "irtt-server",