Add Safari (macOS) parser

[Gear-I]

Summary

• Adds `scripts/artifacts/safariBrowsing.py`, six new artifacts under category "Safari (macOS)": History, Bookmarks, Top Sites, Recently Closed Tabs, iCloud Tabs (CloudTabs.db), and Last Session (open tabs).
• No changes to any existing file -- pure drop-in, picked up automatically by the plugin loader.

Validation

Checked against a real `~/Library/Safari` extracted from Josh Hickman's public macOS Big Sur test image (thisisdfir persona, acquired 2021-02-20), not written from documentation alone:

• History.db: 22 history items / 27 visits, `visit_time` confirmed as Mac Absolute Time in seconds since 2001-01-01.
• Bookmarks.plist: 7 real bookmarks-bar entries; confirmed leaf titles live at `URIDictionary.title`, not the top-level `Title` key.
• TopSites.plist: 12 entries, built-in-vs-earned flagged.
• RecentlyClosedTabs.plist / LastSession.plist: real closed-window and open-tab data recovered; per-tab `SessionState` binary blob intentionally left undecoded (size reported only).
• CloudTabs.db: 2 synced tabs from 1 real device joined via `cloud_tab_devices`.

Co-Author by Claude Sonnet 5