fix(dwg): Add AC1032 version support and improve shell scripts

[marevol]

Summary

• Fix DWG parsing for AutoCAD 2018 (AC1032) files by adding missing version checks
• Improve shell script robustness with proper stderr handling and flexible binary lookup paths
• Add new test targets for dimensions, annotations, and attributes

Changes Made

• DWG Parser (AC1032 support): Added || version >= DRW::AC1032 condition to header (drw_header.cpp) and class reader (dwgreader18.cpp) so the high-size 32-bit field is correctly read for AC1032 files regardless of maintenance version
• Shell scripts (dwg2txt, dxf2txt): Redirected all error/status messages to stderr (>&2) so stdout contains only command output; removed emoji characters for portability
• Binary lookup (dwg2txt): Check installed location ($SCRIPT_DIR/dwg2text) before falling back to development path (../dwg2text/.libs/dwg2text); added installed lib path to LD_LIBRARY_PATH
• Test targets (Makefile.in): Added test_dimensions, test_annotations, and test_attributes build and run targets

Testing

• Existing test suite continues to pass
• New test targets added to autotools build system

Breaking Changes

• None. All changes are backward-compatible.

Additional Notes

• The AC1032 fix addresses files where maintenance version may be <= 3 but the format still uses the extended header size field
• Script changes ensure compatibility with automated pipelines that parse stdout