[codex] restore test parallelism

[winetree94]

Summary

• update the project pnpm version to 11.9.0 and restore workspace/test runner parallelism
• harden frontend e2e startup by disabling Vite HMR in Playwright setup and warming key route modules
• make login/account-selection e2e flows tolerate parallel cold-start and redirect/consent races
• adjust standalone CLI e2e readiness and long-running process timeouts for full parallel test runs

Root Cause

The test suite had several serialized worker settings that kept CPU utilization low. Re-enabling full parallelism exposed timing-sensitive e2e assumptions: Firefox could hit a cold Vite dev server before login route modules were ready, account selection could race between direct redirect and consent, and standalone serve tests could kill long-running CLI processes before they became ready under full-suite load.

Validation

• corepack pnpm test
• corepack pnpm build
• corepack pnpm biome check .
• git diff --check
• targeted Playwright repeats for the previously flaky minimal Firefox login/account-selection flows