feat(routing): choose quota window for earlier reset

[wuchao05]

Summary

Adds a configurable reset window for the existing "Prefer earlier reset" routing behavior. Operators can now choose whether earlier-reset routing is driven by the primary 5-hour quota window or the secondary weekly quota window.

Why

The previous implementation always prioritized the secondary reset window. That made the setting less useful for traffic shaping when the primary 5-hour quota is the tighter operational constraint.

Changes

• Store prefer_earlier_reset_window in dashboard settings with a migration and API/schema support.
• Thread the selected window through account selection and proxy routing.
• Track primary reset timestamps in balancer account state.
• Add a dashboard select for 5h quota vs Weekly quota and update the status bar label.
• Add backend, integration, and frontend tests for the new behavior.

Validation

• .venv/bin/pytest tests/unit/test_load_balancer.py tests/integration/test_settings_api.py -q
• PATH="/opt/homebrew/bin:$PATH" ./node_modules/.bin/vitest run src/features/settings/schemas.test.ts src/features/settings/components/routing-settings.test.tsx src/features/settings/hooks/use-settings.test.ts src/features/settings/components/totp-settings.test.tsx src/features/settings/components/session-settings.test.tsx
• PATH="/opt/homebrew/bin:$PATH" ./node_modules/.bin/tsc -b
• .venv/bin/python -m app.db.migrate check

[wuchao05]

Superseded by #644 so the source branch follows the repository's feat/... branch naming convention.