v1.2.0

Fix critical issues from code review

Fixes #1: Thread safety - read Tkinter vars in main thread
- All StringVar reads now happen in run_optimizer() before spawning worker
- Worker receives parameters as dict argument (thread-safe)

Fixes #2: Add cancellation support to pattern generation
- generate_patterns() now accepts optional stop_event parameter
- Checks for cancellation every 5000 iterations in 2-pipe loop
- Checks for cancellation every 10000 iterations in 3-pipe loop
- Returns partial patterns on cancellation for graceful exit

Fixes #3: Kill CBC subprocess on cancel
- Added _kill_solver_processes() to terminate orphan CBC processes
- Called on cancel button click and window close
- Uses psutil to find and terminate CBC processes

Fixes #4: Add Windows paths to fix_cbc_permissions
- Added win/64 and win/32 paths for CBC solver
- Added documentation about Windows chmod behavior

Issue #5 (memory optimization) deferred - current implementation adequate

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Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>