0.0.4

Adds the docking feature: imgui = { version = "0.0.4", features = ["docking"] } exports the Dock* API surface and the imgui.app facade auto-enables docking. Sources from upstream's docking tag (compat.imgui 1.92.8-docking, superset of mainline — identical behavior with the feature off). Requires mcpp ≥ 0.0.47. See examples/docking.