Fix beta release safety and packaging

[ARCWorksPH]

What changed

• Queues Explorer context-menu selections before the first-run beta notice and forwards them through a current-user-only named pipe.
• Makes archive integrity verification mandatory.
• Removes an entire owned dated copy output after failure when cleanup succeeds.
• Corrects Windows NVMe and virtual bus mappings and uses the seek-penalty descriptor for HDD/SSD concurrency decisions.
• Limits Extract context-menu selection to one archive.
• Updates the project to 1.2.1-beta4 and refreshes the questionnaire, instructions, build status, and package metadata.

Why

The beta3 GitHub release exposed only the installer even though the documentation promised four downloads. Review also found a first-launch multi-selection race, optional archive verification, ambiguous failed-copy output, and incorrect storage classification.

User impact

Testers receive a complete four-file beta package. Explorer multi-selections are retained during first launch, archives cannot be published without verification, failed copies are cleaned up conservatively, and copy concurrency is safer on HDDs.

Validation

• Release build: 0 warnings, 0 errors
• Unit tests: 48 passed
• Integration tests: 26 passed
• Self-contained Windows x64 publish: passed
• Inno Setup 6.7.3 compilation: passed
• Questionnaire: 5 pages rendered and visually inspected
• Package: exactly 4 files
• Installer SHA-256: 162609476CB264F969AF0DDD99F8E71954B4659CF5504AAA08A464F5B86B7022