Meet Sudoku

### Additions and Improvements - Added Undo support, fully integrated with actions like color marking - Added multi-color marking; supports continuous coloring by holding down the mouse button - Added a wide range of color themes - Added selection styles and cursors; included previews for the grid and selection states - Grid line settings are now freely adjustable - Chain drawing (dashed lines) supports adjustable thickness and spacing - Key bindings for cross-border input now support key combinations - Optimized multi-selection with two modes: "Mouse Multi-select" and "Key Multi-select" - Mouse Multi-select supports continuous selection via click-and-drag - Key Multi-select supports customizable modifier keys (e.g., Shift) - Optimized selection, note-taking, and highlighting logic for "Number-First" mode - Optimized candidate highlighting and added a feature introduction - Automatic note clearing now synchronizes with Variant Sudoku rules - In "Fog of War" mode, notes can now be added to locked cells, though numbers cannot be entered directly - Optimized technique hints; added options to select or deselect all techniques - Added an option to exit training mode from the technique hints menu - Added an option to hide tutorial prompts - Added a button to exit the tutorial - Merged the Pause menu and the ESC menu - Simplified the difficulty of daily goals - Optimized the difficulty sorting for Sudoku techniques ### Variant Sudoku Improvements - Optimized display scaling for Variant Sudoku overlays (e.g., XV, Odd/Even) to fit various screen sizes and devices - Irregular (Jigsaw) Sudoku regions now use distinct region lines; original standard region lines removed - Optimized Killer Sudoku cage borders, dividers, and top-left digit displays - Generated a "Normal" difficulty puzzle bank for Killer Sudoku - Optimized Variant Sudoku rules and automatic note-clearing logic ### Sudoku Techniques - Audited the Sudoku technique puzzle bank; regenerated example puzzles that did not meet requirements - Fixed issues with multiple solutions in Sudoku technique tutorial levels - Corrected erroneous descriptions regarding the "Empty Rectangle" technique - Fixed inconsistencies between automatic and manual chain drawing results Optimized the logic for determining strong and weak links during the chain-drawing process - Drag-selecting no longer accidentally triggers the highlighting of identical numbers