feat(stats): Stats view with quota and 5-hour session forecasts (1.7.0)

[StevenACZ]

Summary

• Stats face behind the panel (flip), scoped to the selected tab: weekly and 5-hour session forecasts from the server percentage, today vs a usual day, 14-day chart, totals, streaks, models, effort, most used skills, turns and cache share. Cards collapse and remember it.
• 5-hour session verdict under the session ring in the Claude and Codex views.
• Forecasts treat time on another Claude account as a marked gap instead of pace or an early reset.
• History records skill names and turn durations (no content); the cold scan checkpoints and resumes.
• SwiftUI period/year controls, centered streak; in-panel clicks after a reopen no longer close the popover.
• Version 1.7.0 (build 10), CHANGELOG and README (synthetic Stats screenshot).

Verification

• make ci-check: 256 tests, 4 opt-in skips, 0 failures; make lint, git diff --check, gitleaks clean.
• Clean-profile QA on a second Mac: Stats flip, forecast rows, hourly chart, collapse persistence across relaunch, popover stays open on in-panel clicks.