Phase 1: Complete Transform Tools — Scale Gizmo, Local/World Space, Keyboard Shortcuts

[fernandotonon]

Goal

Fill the most critical functional gap — add scale gizmo, local/world transform space toggle, and remap keyboard shortcuts to Unity convention.

1a. Scale Gizmo

• Create ScaleGizmo.h/cpp following TranslationGizmo pattern (Ogre::ManualObject with per-axis cube handles)
• Add TS_SCALE to TransformOperator::TransformState enum
• Wire in updateGizmo(), mousePressEvent(), mouseMoveEvent()

1b. Local/World Transform Space

• Add TransformSpace enum to TransformOperator
• Orient gizmo to selected node's rotation when LOCAL
• Toolbar toggle + keyboard shortcut X

1c. Keyboard Shortcuts (Unity convention)

• Q=Select, W=Translate, E=Rotate, R=Scale, F=Frame selection
• Add SpaceCamera::frameSelection() for F key

Depends on: Nothing (can start immediately)
Part of: UX Redesign Roadmap