Fix ride page stuck on swipeable loading cards

[rijuyuezhu]

Summary

• replace the shared initialization-cancellation boolean with a generation token so stale async work cannot overwrite a newer RidePage initialization
• keep ride-history preference sorting on the startup path cache-only, then refresh history through the shared RideHistoryProvider after the ride cards are usable
• guard async card/QR/auto-reservation writes against stale generations
• add a widget regression that stalls the first initialization, retries, then releases the stale request and verifies no 加载中... cards remain

Validation

• flutter test — 17 passed
• flutter analyze --no-fatal-infos — only 2 pre-existing surfaceVariant deprecation infos
• git diff --check
• secret scan — no findings

Reproduced on v3.1.7 as two swipeable RidePage cards both showing 加载中....

[rijuyuezhu]

Closing temporarily to revise the PR description before resubmitting.