M165: Add first functional Train workspace

[Coasterpete]

Summary

This milestone introduces the first functional Train Workspace to the Quantum CoasterWorks Avalonia editor.

M165 focuses on a stable engineering foundation built on the existing immutable backend train types while preserving the architecture established in previous milestones.

What's Included

• Enabled the Train workspace profile
• Added Train Configuration, Preview, and Summary panes
• Atomic editing of:
  • Car count
  • Car-center spacing
  • Car body length
  • Car body width
  • Car body height
  • Bogie spacing
• Validation using the existing immutable backend:
  • TrainConsistDefinition
  • TrainCarGeometry
  • TrainBogieLayout
• Preservation of the last valid consist after invalid edits
• Deterministic top-view consist schematic
• Calculated engineering readouts:
  • Approximate consist length
  • Inter-car gap
  • Car dimensions
  • Bogie spacing
• Independent Track and Train docking layouts
• Workspace-specific command visibility
• Documentation and automated tests

Architecture

• Backend train types remain the authoritative source of truth.
• No duplicate Avalonia train-domain model was introduced.
• The frontend stages edits before atomically constructing immutable backend definitions.
• The preview is intentionally schematic so future visual train assets can be added without changing the consist model.

Verification

• ✅ dotnet build QuantumCoasterWorks.sln --nologo
• ✅ dotnet test QuantumCoasterWorks.sln --no-build --nologo
• 1,816 tests passed
• Zero build warnings or errors

Manual smoke testing verified:

• Track ↔ Train workspace switching
• Consist editing and validation
• Preview updates
• Summary calculations
• Independent workspace layout persistence
• Returning to Track preserves the existing Track workspace state

Deferred

This milestone intentionally does not implement:

• Train asset importing
• .glb / .gltf train models
• Train style packages
• 3D visualization
• Seats or restraints
• Wheel assembly editing
• Articulation editing
• Train-on-track placement
• Physics playback
• Simulation controls

These capabilities are planned for future milestones built on top of the Train Workspace foundation.

Screenshots

Track Workspace

Engineering Math Plots

Train Workspace (M165)

Workspace Switching

95a0f22d73540e21b95646eeb13fa8e2.mp4