feat: Safari classifier with per-tab/domain renderer grouping

[alecf]

Summary

Safari uses the same multi-process architecture as Chrome — Web Content renderers, a GPU process, a Networking process, and SafariWebExtension processes — but all of them show up as opaque com.apple.WebKit.* processes today.

A dedicated SafariClassifier would:

• Claim all processes whose bundle ID starts with com.apple.Safari or whose path includes Safari.app or WebKit.framework
• Group renderer processes by domain (the URL or hostname is visible in process args for Web Content processes)
• Label sub-processes by type: Web Content, GPU, Networking, Extension

Value

Same "aha moment" as ChromeClassifier: users can see which website tab is consuming the most memory, and get a single rolled-up Safari footprint rather than a pile of mystery WebKit processes.

Implementation notes

• Detection: com.apple.Safari bundle ID, Safari.app in path, com.apple.WebKit.WebContent / com.apple.WebKit.GPU / com.apple.WebKit.Networking process names
• Domain grouping: parse --origin-to-launch-process or similar arg that WebKit passes to content processes; fall back to grouping all renderers under "Web Content"
• Icon: NSRunningApplication lookup on the main Safari process
• stableIdentifier: "safari" (single top-level group, sub-groups by domain)