Use portable POSIX parent paths instead of platform-dependent dirname() for remote navigation, previews, uploads, file operations and shared URLs.
Normalize browser paths, avoid doubled root separators and preserve top-level directory names in ZIP downloads.
Add regression coverage for root navigation, generated links, relative paths and ZIP members, and document the new test command. Verified with PHP syntax checks and all three regression suites.
Expand README with application features, requirements, XAMPP setup, connection configuration, project structure and troubleshooting.
Add Czech database documentation covering SQL import, manual SQL and phpMyAdmin table setup, bcrypt administrator creation, database permissions and verification.
Provide the missing share table schema as a separate SQL supplement and explain its relationship to the original users dump.
Michal Sedlák