v0.4.3: Toolbar UI

UI update — unified Toolbar

• Renamed the Transform tab to Toolbar and moved the Plates button into it
• Migrated Move and Rotate out of the (now removed) Orientation tab
• Laid out all desktop-style model tools in one place: Plates, Auto-orient, Arrange, Split, Variable layer height, Move, Rotate, Scale, Lay on face, Cut, Support/Seam/Fuzzy/Color paint, Emboss, Measure

Working tools are wired up; tools not yet implemented show a clear message when tapped.

Bottom tabs are now: File · Camera · Toolbar · Slice.