desktop: align the git, memory and driver labels with the phone #1571

Problem

The phone app clarified three workspace labels in #1563 and #1565; Stim Desktop still shows the old forms:

1. The workspace header's git pill shows bare arrows (↑4 ↓3), which don't say that they count commits not pushed and commits behind the upstream.
2. The workspace memory pill (4.6 GB, the committed estimate from stim status) has no label or icon, so it reads like disk.
3. Every driven device tile carries its own "Driven by · " pill, so a workspace with several driven devices repeats the driver.

Evidence

apps/desktop/Sources/StimDesktop/Views/Components.swift (GitIndicator chips), Views/WallView.swift and Views/WorkspaceDetail.swift (memory pill), Views/DeviceTile.swift (activityChip) on origin/main.

Cause

Not a defect; the phone changed first.

Fix idea

Polish changes, one commit each:

• Git: separate "↑N unpushed" and "↓N behind" pills with spoken labels ("4 commits not pushed", "3 commits behind the upstream").
• Memory: a memory-chip icon and the label "Estimated to use about 4.6 GB of memory".
• Driver: one driver pill per workspace header (tools once, time since the latest start, like the phone's driversSummary), and a compact accent "Driven" pill with a dot on each driven tile.