Fix macOS menu bar label render loop

[skuznetsov-clickhouse]

Summary

• replace TimelineView in the MenuBarExtra label with one app-owned minute clock
• share the same clock with quota countdowns in the popover
• add a deterministic publisher-driven clock test

Root-cause validation

• merged main release: 100.0% CPU after 9 seconds
• stable fresh TimelineView anchor variant: 100.0% CPU after 11 seconds
• timer-based release: 0.0% CPU after 7 seconds and again after 1 minute 17 seconds

The stable-anchor result refutes the narrower claim that a changing .now schedule identity is required. The failure is the self-updating TimelineView inside the MenuBarExtra label; removing that combination fixes the spin.

Verification

• Swift tests with warnings-as-errors: 38 passed, 0 failed
• Swift release build with warnings-as-errors: passed
• runtime before/after CPU probe: passed

Skipped gate

• no screenshot-based visual confirmation of the status item; screen capture was intentionally not used because it could expose unrelated menu-bar information.