LRGEX-Compress Files

✨ New Features

• Integrity checksum: .zgx archives now include zstd XXHash64 checksum verification on extract. Detects storage corruption, bad transfers, and bit rot before you lose data. Zero measurable speed cost (~6ms per 256MB — within run-to-run noise).
• RAR extraction rewritten in pure Rust: replaces the vendored C unrar library with unrar-rs (pure Rust, no C dependencies). Adds:
• Symbolic link preservation (asks admin once, recreates links exactly)
• mtime + ctime restore on extracted files
• Windows attributes restore (ReadOnly, Hidden, etc.)
• Instant mid-file cancel (custom Writer aborts on cancel flag)
• Multi-volume support (part1.rar, part2.rar, ...)
• 7z metadata restore: extracted 7z files now preserve mtime, ctime (when carried), and Windows attributes.
• 7z symlink support: symlinks stored as reparse points in .7z archives are now detected and recreated (with path-traversal guard for security).
• Instant feedback on click: the progress window now shows an animated sweep the moment you click Compress or Extract — no more frozen 0% bar while the engine spins up.
• Encrypted archive support: password-protected RAR, 7z, and ZIP archives now prompt for a password. GUI shows a masked password dialog with auto-focus. CLI: -p <password> flag works in any position. Example: lrgex-compress -x -p secret archive.rar

🔧 Fixes

• 7z overwrite+cancel data loss (critical): extracting a .7z over an existing file, then cancelling, no longer destroys the user's original file. All 7z extraction now uses temp-then-rename (same safe pattern as .zgx and .zip).
• ctime clobber on every extract (critical): every extracted file was getting creation time set to January 1, 1970. The bug was in apply_times_handle — secs_to_filetime(0) is NOT a zero FILETIME (it's 1601+epoch_offset = 1970-01-01). The "NULL if zero" guard never fired. Fixed: branch on the INPUT value, not the converted FILETIME.
• 7z mtime lost: 7z extraction was giving every file NOW() as last-modified time. Now reads entry.last_modified_date() from sevenz-rust2 and restores it.
• Checksum failure silently swallowed: include_checksum(true) was discarding the Result with let _ =. Now propagates via .expect() — a checksum failure surfaces as an error instead of silently shipping without integrity.
• Test harness pipe deadlock: integration tests could hang when the spawned exe produced >64KB of stdout (pipe buffer fill). Fixed with Stdio::null().

🧪 Quality

• 49 automated tests covering every format, every metadata field, cancel, multi-volume, crash-safety, and overwrite+cancel data-loss scenarios.
• No #[ignore]d tests hiding gaps — every test runs automatically.
• RAR + 7z tests auto-detect external tools (WinRAR / 7-Zip) and run when present.
• Vendored C unrar crate removed (210KB of C source). RAR extraction is 100% pure Rust.
• License: switched from MIT to GPL-3.0-or-later (unrar-rs is GPL-3.0 + UnRAR restriction).

⚠️ Known Limitations

• 7z symlinks: requires Administrator or Developer Mode to create symlinks on Windows. Without elevation, symlinks in .7z archives are skipped silently.
• zip ctime: the ZIP format has no creation time field — cannot be preserved.
• 7z ctime: 7-Zip does not store creation time by default (only with -mtc=on). Restored when present, absent when not.
• RAR4: unrar-rs claims support but could not be tested (WinRAR 7.23 creates RAR5 only).
• Encrypted archives: password-protected RAR, 7z, and ZIP are supported via GUI prompt or -p <password> CLI flag. However, the GUI window stays open briefly after extraction completes (auto-close delay). Scripted/headless use with -p blocks until the window is closed manually.