Snapmaker Orca FullSpectrum v0.9.6

Mixed-filament bias controls, preview updates, and release cleanup. Based on Snapmaker Orca v2.3.1.

Highlights

Added an optional per-pair Bias control for mixed filaments.
Positive bias recesses the second filament in the pair.
Negative bias recesses the first filament in the pair.
Added clamping and signed-bias handling so the slicer and UI use the same safe range.

Added a print setting to enable or disable mixed-filament bias mode.
Moved the bias control inline with the mixed-filament preview row to keep the editor compact.
Added apparent-color preview feedback so biased pairs can show an estimated shifted mix in the UI.
Simplified the final bias workflow so the control behaves consistently across mixed filament pairs.

Applied bias through the mixed-filament slicing path so recessed layers affect generated geometry instead of only the editor preview.
Fixed mixed-filament panel refresh behavior when the bias setting is toggled.
Improved preview behavior for biased mixed filaments and reduced mismatches between the row preview and sliced output.
Fixed region handling so recessed mixed-filament space is not immediately refilled by the other component in the common painted path.

Bumped the FullSpectrum version to 0.9.6.
Moved older changelogs and release notes into doc/changelogs/ and updated the release workflow to read them from there.
Refreshed the README mixed-filament section to document the Bias feature and added a compatibility warning for older .3mf projects.

Expanded test_mixed_filament.cpp coverage for signed bias, clamping, serialization, and remapping behavior.
Rebuilt libslic3r_gui.
Rebuilt libslic3r_tests and re-ran the [MixedFilament] suite successfully.

Some .3mf files created with older FullSpectrum builds may not load or migrate cleanly in newer versions because mixed-filament project data has evolved.
macOS builds from this fork remain unsigned and not notarized.
Use at your own risk.