feat(config): support human-readable durations with legacy compatibility

wakey-core/Cargo.toml

@@ -17,6 +17,8 @@ time = { version = "0.3", features = ["formatting", "local-offset"], optional =
 tonic = { version = "0.14", default-features = false, optional = true }
 macaddr = { workspace = true }
 serde = { workspace = true }
+serde_json = { workspace = true }
+humantime = "2"
 serde_with = { version = "3", features = ["json"] }
 strum = { version = "0", features = ["derive", "strum_macros"] }
 thiserror = "2"