[codex] Dock native file viewer toolbars

[ActiveInAI]

Summary

• Add a reusable dockable viewer toolbar with left/top/bottom/right docking and drag-to-nearest-edge behavior.
• Move CAD/engineering, PDF, Office, text/data, archive, image, audio, video, and HTML viewer controls into side-docked toolbars by default.
• Let ZIP entries open inline previews for text, image, PDF, Office, CAD/BIM, and nested ZIP entries from the real archive bytes.
• Improve DWG fallback by prioritizing real source summary and embedded raster preview extraction while keeping geometry behind licensed/isolated adapter routes.

Verification

• bun run typecheck
• bun run lint
• bun run test
• bun run build
• python3 tools/production_readiness_contract.py
• Playwright screenshots: /app/modules/detailed_design, /app/modules/quantity_costing, /app/modules/digital_twin