Add hourly pace section to usage card and menu

[johnlarkin1]

Summary

• Adds session-level hourly pace indicators to both the usage card (MenuCardView) and the text-based menu (MenuDescriptor)
• Shows current consumption rate vs. sustainable pace (e.g., "2.1/hr vs 1.5/hr pace") with a colored progress marker
• Extends UsagePaceText with sessionSummary and sessionDetail methods for session-scoped pace computation

Changes

File	Change
MenuCardView.swift	Compute + display session pace detail (left/right labels, pace bar)
MenuDescriptor.swift	Add pace summary line to text menu
UsagePaceText.swift	New sessionSummary/sessionDetail methods
UsagePaceTests.swift	Tests for session pace computation
UsagePaceTextTests.swift	New test file for text formatting

How it works

The pace calculation divides current session usage by elapsed hours, then compares to the sustainable rate (limit ÷ window hours). The card view renders this as a secondary progress bar overlay, while the text menu shows a one-line summary.

Test plan

• Builds cleanly on upstream/main (swift build)
• swift test --filter UsagePaceTests passes
• swift test --filter UsagePaceTextTests passes
• Verify pace indicators render correctly in menu card for providers with session windows

🤖 Generated with Claude Code