[Thijs226]

Both generated manifests omit storage, although the background script, logger and popup use browserAPI.storage.local. In a fresh Chromium installation, chrome.storage is undefined: installation statistics and save counts never persist, diagnostic entries are discarded, and rating preferences cannot be saved.

Add storage to the shared manifest template for Chrome and Firefox, update the existing manifest contract test, and document the local data in the README and privacy policy. No new data collection or network behavior is introduced.

Verified on a disposable VPS workspace:

• Reproduced the missing API and empty saved statistics/diagnostics in Chromium before the fix.
• After rebuilding, verified installation time, save count increments, persisted diagnostic entries, and popup rating preferences surviving reload in Chromium.
• All 102 Jest tests pass with the configured coverage thresholds.
• Prettier formatting/check, ESLint, and Chrome/Firefox builds pass. Temporary tooling and generated coverage were excluded from formatting/lint traversal; tracked source was checked.

The permission requirement is documented by Chrome and Mozilla. Firefox's generated manifest is covered by tests; the live browser check used Chromium.