[hanhan-sigmaz-code]

CI previously failed workflow validation because job-level env referenced runner.temp, which is unavailable in that context. Initialize the isolated runtime paths after runner startup so setup and tests can execute on macOS and Windows.

The first working CI runs also exposed test-environment dependencies. This change:

• Gives the offline review-price test an isolated configuration, a dummy key and a pinned model instead of relying on personal credentials or cached settings.
• Uses asynchronous fixture copying to preserve the standalone installation test's Chinese and space-containing paths on Windows with Node.js 22.
• Runs test files sequentially to reduce competing browser renders during real-time recording tests. All existing assertions and the macOS/Windows × Node.js 22/24 matrix remain enabled.

Validation:

• actionlint 1.7.12 and git diff --check pass.
• Local full suite: 208 passed, 0 failed, 1 existing skip.

Required CI checks are intentionally deferred. The active main ruleset requires one approving review, dismisses stale approvals, requires resolved review conversations, blocks force pushes and deletion, and has no bypass actors. This PR needs an independent approval before merge.