Summary

Reorganizes .gitignore entries for bundled dependency symlinks from the root file into library-specific .gitignore files, and adds missing entries for PDF and Net libraries.

Changes

New library-specific .gitignore files created:

Root .gitignore cleanup:

Removed 55 lines of bundled dependency symlink entries that are now managed in their respective library subdirectories.

Key improvements

1. PDF/src symlinks were completely missing - png and hpdf files created by prebuild step are now properly ignored
2. Net/src/wepoll.c was missing - symlink for MinGW builds is now properly ignored
3. Better organization - each library manages its own bundled dependency symlinks
4. Maintainability - easier to update when dependencies change

Related

Closes #5048