feat: redesign DevDeck as a hybrid command center

[writingdeveloper]

Summary

• redesign DevDeck as a cleaner Orca-inspired hybrid command center
• unify project scanning, live-session access, and responsive Project Memory flows
• add stable session restoration, previous-session controls, visible status labels, and a 520px session drawer
• align Tasks, Usage, Settings, dialogs, menus, icons, and accessibility behavior with the shared design system

Verification

• npm run build
• npm test — 878 passed, 1 platform-specific skip
• npm run qa — all desktop/520px and four-language scenes passed with 0 console errors and 0 page errors
• npm run qa:audit — 0 accessibility violations across every audited view and dialog
• GitHub CI — Linux/macOS/Windows build, test, package, and Linux IPC/a11y audit passed
• git diff --check