refactor: remove dead code, redundant wrappers, and low-value tests

[MyButtermilk]

Scriber still carried unused UI implementations, generated component scaffolding, obsolete entry points, and forwarding helpers. Some tests only asserted CSS values, source spelling, constants, or code that no longer had callers. These made routine changes harder to review without protecting useful behavior.

This cleanup removes 2,046 net lines across 55 files.

Changes

• Remove the unused recording popup, standalone WebSocket hook, obsolete Outlook formatter, and 23 unused UI component exports/implementations.
• Simplify the default query function to its sole used strict behavior; remove unused upload/display helpers and redundant date normalization.
• Remove unreferenced backend/store/controller methods, the obsolete Gemini 1.5 demo, and its optional-import exemption. The supported Gemini providers remain intact.
• Call the existing environment, device-name, vocabulary, and diagnostic-hash helpers directly; consolidate identical subprocess cleanup blocks.
• Remove unreachable native tray menu builders while preserving the active React tray panel, shared actions, and validated recent-copy smoke path.
• Remove the retired Python desktop bootstrap and unused benchmark/release helpers.
• Remove 32 low-value or duplicate tests. Preserve the useful background-refresh assertions from a mixed type/source snapshot and document the distinction between behavior tests and meaningful source contracts.

All deleted application symbols were checked for callers across the repository. The audit covered the frontend, backend/API/runtime, native shell, scripts/packaging, extension, benchmarks, and historical ML area. Historical ML evidence, platform hooks, public domain boundaries, security checks, cancellation ownership, and packaging locks were retained. No dependency or model upgrades are included.

Validation

The complete Hybrid PR Checks run 361 passed for final head 7c9b5914d74714d44a12e1cc032b9b8ccab9aba0.

• Python full suite: 4,221 passed, 5 skipped on Windows.
• Rust: 303 passed, with formatting and Clippy also passing.
• Frontend: 109 library tests + 63 component tests passed; application/test typechecks, ESLint, and production build passed.
• Extended Python mypy: no issues in 77 source files.
• Real-browser File upload smoke passed against React/Vite, the production Python app, file route, durable job store, and WebSocket route. No browser console errors, page errors, or unhandled rejections were recorded.
• Repository-wide Python Ruff, focused hybrid gates, QuickJS cache verification, and GitHub Actions syntax passed.
• Independent diff review found no blocking runtime regressions. The configured Codex reviewer left a thumbs-up; there are no open review comments or threads.

The five Python skips concern optional locked QuickJS/FFmpeg and shipping-native-runtime qualification conditions. Earlier Linux-only failures were documented during local validation; the full Windows CI suite now passes. The browser smoke holds the provider worker at the queued-job boundary. Installed-app, physical-device, and external-provider checks were not run; no installer or release was built.

CI evidence

1. https://github.com/MyButtermilk/Scriber/actions/runs/33947218495