chore: Add build directories to .gitignore

Add build_*/ pattern and linux/build_scan/ to ignore various build
output directories (build_ocr/, build_ocr_asan/, etc.)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: cfsmp3

.gitignore

@@ -17,6 +17,7 @@ CVS
 mac/ccextractor
 linux/ccextractor
 linux/depend
+linux/build_scan/
 windows/x86_64-pc-windows-msvc/**
 windows/Debug/**
 windows/Debug-OCR/**
@@ -28,6 +29,7 @@ windows/Debug-Full/**
 windows/x64/**
 windows/ccextractor.VC.db
 build/
+build_*/
 
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 # Python