Add Roblox Windows forensic artifacts

[abrignoni]

Summary

• add Windows-specific Roblox account, presence, notification, and game-join artifacts
• parse WebView2 history and focused JSON evidence for account, social, commerce, messages, and user content
• add Chromium blockfile cache decoding and strengthen shared Roblox decoding
• suppress empty session-state and low-value cache output

Validation

• 13 targeted parser/import tests passed
• changed-file pylint: no new warnings
• byte-compilation and git diff checks passed
• full Windows corpus run completed with no parser errors

Scope

Runtime parser files only. Local profiles, test fixtures, generated reports, and corpus data are intentionally excluded.