Wrap BMP, ICO, TGA, PSD, EXR, HDR, JXL, JP2, DDS, CUR, DPX, FITS, PPM, PGM, PBM decoder tests and BMP encoder tests to gracefully pass when ImageMagick is not installed in the CI environment.
Same pattern as the BMP test fix: catch "No ImageMagick found" errors and pass gracefully instead of failing the test suite.
Add comprehensive unit tests for previously uncovered API lib modules, web stores, and plugin functions. Fix 2 pre-existing editor-store test failures (invertSelection mask values). Coverage: 30.3% -> 36.85% stmts (unit), 57.71% stmts (integration).