v2.1 test build (#360, 64-bit crash fallback)

Test build for #360 (Windows). Not a release; 2.1 stays the stable version.

• If the 64-bit game closes with an error, the launcher now offers to keep playing in 32 bits (same saves and settings) and a one-click report.
• Crash details (system, exception, stack) are written into kh_com.log; the report bundles it with the 5 previous sessions in ReKHCoM-reporte.txt.

SHA256: d074a0812fd6fea1bd18f70f29a5c80533304bbd00ad6592b41c948818052876