Validate v1.1 across the workbench and prepare store release artifacts #11

Purpose

Before submitting the unpublished v1.1.0 update, verify the entire browser
workbench, fix reproduced defects, and prepare reviewable release artifacts.

Acceptance criteria

• Audit each tool and run syntax/regression checks and isolated browser tests.
• Extend coverage for untested request, storage, import/export and UI paths.
• Fix reproduced bugs and add meaningful regression coverage.
• Verify macOS and Windows shortcut hints, dark/light themes and narrow UI.
• Build a runtime-only ZIP and signed CRX with the existing local signing key,
  without reading/printing key contents or including keys in artifacts.
• Verify archive contents, version, CRX signature and package correspondence.
• Prepare store-sized actual UI screenshots, listing/update text, privacy and
  reviewer instructions, and a feature-by-feature verification report.
• Submit source changes in a new PR; stay at v1.1.0 and do not publish the
  store update automatically.

All tests use local fixtures and isolated profiles. GitHub/store publication is
separate from preparing the local upload bundle.

Implemented and verified in PR #13. Keep this issue open until the PR merges. Version 1.1.0 remains unpublished.