refactor: migrate modules to src/, add logging system, add assembly workshop

refactor: Complete ESKD archive system - rewrite append_document, fix typos, enhance UL generator, add date masking, and improve PDF preview engine

fix: Restore init_cache() function

chore: Add __pycache__/ to .gitignore

refactor: Remove __pycache__ from git tracking

refactor: migrate modules to src/, add logging system, add assembly workshop

refactor: Complete ESKD archive system - rewrite append_document, fix typos, enhance UL generator, add date masking, and improve PDF preview engine

fix: Restore init_cache() function

chore: Add __pycache__/ to .gitignore

refactor: Remove __pycache__ from git tracking

Fix critical issues:

Initial commit: PDM/СЭД система для ЕСКД