v0.1.5

Added

• Composite Page Overlay Images:
  • Support parsing and compositing sub-images onto the base canvas for composite CHM pages (e.g. answer key overlay patch images AS011_*.YBM on exercise pages).
  • Preserved underlying background and base page hotspots when overlay documents have no conflicting click targets.
  • Automatic overlay state cleanup upon page navigation.
• NTSC Video Stream Support:
  • Extended MPEG-1 video decoder and player to support NTSC dimensions (352x240 @ ~29.97/30.0 fps) alongside standard PAL (352x288 @ 25.0 fps).

Fixed

• Underline Hotspot Hit-Testing:
  • Added upward click tolerance for thin underline hotspots (e.g. fill-in-the-blank questions in exercise pages), allowing clicks in the blank space directly above the underline to register properly.
• Video Playback Concurrency & ESC Handling:
  • Resolved lock contention and deadlock when pressing the Escape key during active video playback, ensuring instant return to the preceding CHM page.