Fix FloatBar weekly usage fallback

[bohacf]

Summary

• use the secondary usage window in FloatBar when the primary window is informational
• apply the same effective window to percentage, reset time, exhaustion tone, and provider sorting
• add regression coverage for weekly fallback behavior and tone calculation

Related issue

Fixes #275

Affected areas

• Tray panel
• Settings UI
• Config file / settings persistence
• CLI
• Provider-specific behavior
• Installer / release packaging
• Startup / background behavior
• Documentation
• Other: FloatBar

Validation

• powershell.exe -ExecutionPolicy Bypass -NoProfile -File scripts\local-check.ps1
• For full pre-release validation: powershell.exe -ExecutionPolicy Bypass -NoProfile -File scripts\local-check.ps1 -All -Version <version>
• For installer/release changes: powershell.exe -File scripts\windows-release-build.ps1 -Ref <ref> -SmokeInstall
• Thermo-nuclear code quality review completed before submitting: https://github.com/cursor/plugins/blob/main/cursor-team-kit/skills/thermo-nuclear-code-quality-review/SKILL.md
• Other:
  • vitest run src/floatbar/FloatBar.test.tsx — 17 passed
  • full frontend vitest run — 40 files / 248 tests passed
  • locale drift check, TypeScript check, and Vite production build passed
  • tauri build --debug --no-bundle completed successfully on Windows

UI / tray proof

• Not applicable
• CUA Driver visual proof attached
• CUA Driver could not be used; equivalent manual proof and explanation attached

CUA Driver was not installed on the test machine. A fresh debug build containing this change was tested manually on Windows 11 against the affected Codex OAuth account, and manual testing confirmed that the FloatBar now shows the weekly usage correctly.

Notes for reviewers

The fallback is intentionally local to FloatBar. Provider normalization and the bridge contract already expose the canonical informational primary window introduced by #268.

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[bohacf]

Closing as a duplicate of #277, which implements the same FloatBar fallback with shared usage-window selection and broader regression coverage.