fix(monitoring): show account cache read and write metrics

[seakee]

Summary

Fix the request-monitoring account overview so its cache slot displays fine-grained cache reads and writes instead of showing zero when legacy cached tokens are absent.
The responsive layout remains unchanged and legacy cache-only models keep their existing presentation.

Scope

• Frontend panel
• Manager Server
• CPA panel mode
• Full Docker mode
• Native packages / release
• Docs / Wiki
• CI / build / tooling

Changes

• Format account cache metrics adaptively as legacy cache, CR, CW, or a compact combination of the available buckets.
• Apply the shared cache presentation to desktop token structure, mobile token cards, desktop model tables, and mobile model details.
• Preserve the existing single cache slot and responsive dimensions without adding cards, rows, or table columns.
• Add regression coverage for legacy, fine-grained, mixed, and zero-cache states.

User Impact

GPT-5.6 account summaries no longer show cache usage as zero when requests contain cache reads or cache writes. Users can distinguish cache hits from cache creation directly in both desktop and mobile monitoring views.

Compatibility / Runtime Notes

• CPA panel mode: Uses cache fields already present in monitoring data and does not require CPA PR #4193.
• Manager Server mode: No backend or API changes.
• Full Docker / native packages: Frontend-only behavior change with no configuration or migration.

Data / Security Notes

N/A. No persistence, authentication, key handling, raw usage data, or export behavior changes.

Risk / Rollback

Risk level: Low

Rollback notes:

• Revert commit c00daa9.
• The previous single legacy-cache value will be restored with no data rollback.

Verification

• Type check
• Lint
• Tests
• Build
• Manual UI check
• Docs/link check
• Not applicable, docs-only

Commands / evidence:

npm run type-check
npm run lint
npm run test
npm run build
git diff --check

Frontend result: 86 test files, 741 tests passed.

Screenshots / Recordings

Not captured. Server-rendered component tests verify the desktop table and shared responsive cache presentation for C, CR, and CW states.

Docs

• README updated
• Wiki updated
• Release notes needed
• Not needed

Related

Refs #338