v0.4.21

What's Changed

• Model-View-ViewModel (MVVM) in @semiont/api-client by @adampingel in #649
• MVVM follow-up by @adampingel in #650
• work pool in separate process by @adampingel in #651
• fixes for separate worker pool and smelter containers by @adampingel in #652
• collapse backend routes to generic event bus handlers; steps 1-3 by @adampingel in #653
• unified bus actor by @adampingel in #654
• bug fixes from unified bus actor, and previous changes by @adampingel in #655
• user testing by @adampingel in #656
• Semiont Session by @adampingel in #657
• SemiontSession to @semiont/api-client, and other follow-ons by @adampingel in #659
• fix job event handling (progress, etc.) by @adampingel in #660
• OpenAPI sync; SemiontSession for workers by @adampingel in #661
• rm fallback by @adampingel in #662

Full Changelog: v0.4.20...v0.4.21