v0.4.0

Breaking

• Refactored core device APIs to be target-aware and fallible: getters/setters now use Result-based return values and explicit device selection.
• Removed implicit fan-out writes when multiple dongles are connected; commands now require -s/--device BB:DD in multi-device scenarios.

Added

• Added typed core error model (MdropError) and result alias (MdropResult) for transport, selection, and payload failures.
• Added DeviceSelector to support explicit bus-targeted operations.
• Added payload validation and strict enum parsing (TryFrom<u8>) for filter/gain/indicator state.
• Added optional clap feature in the core crate to enable ValueEnum derives when used by CLI consumers.
• Added JSON output mode for get and devices commands.

Changed

• Updated CLI and GUI to use the new result-based core API.
• Restored CLI set argument value hints by enabling core enums as clap ValueEnum behind feature flag.
• Improved GUI update loop to avoid synthetic disconnect flicker and handle watch/update failures without panics.
• Updated Nix and workspace dependencies, including migration to newer Iced.

Fixed

• Fixed overflow when setting volume to 100.
• Improved USB/watch failure handling by replacing panic-prone control flow with surfaced errors.

Docs

• Updated README.md to document deterministic device selection behavior and multi-device usage requirements.

Full Changelog: 0.3.0...0.4.0