Build 24948906

Note: Projects saved with the new version may require re‑parsing.

1. Add Isometric / Orthogonal (Top‑down) view mode switching;
2. Isometric coordinate system: diamond projection for grid, terrain, and objects;
3. Bidirectional isometric<->orthogonal coordinate conversion utilities (isoCoordinateUtils);
4. Isometric terrain rendering: diamond warp transform, shares 2x2 vertex stamp with orthogonal;
5. New Map dialog supports view mode selection (Top‑down / Isometric);
6. Settings dialog supports view mode change;
7. Top toolbar adds view mode toggle button;
8. Isometric object projection: pivot‑aware isometric display for character/attachment anchor alignment;
9. Open old map JSON with compatibility: fill missing fields, migrate English layer keys, densify sparse terrain, rewrite legacy resource folders;