- Removed export leakage by demoting many helper and const symbols to module-local scope.
- Renamed underscore-prefixed internals and cache fields, then updated related references and `satisfies never` checks.
- Deleted obsolete logic branches and helpers, including harmony-stream interruption flow and unused benchmark runtime helpers.
- Updated Biome config and manifests by broadening lint coverage and removing an unused `@napi-rs/cli` dev dependency.
- Adjusted tests and utilities to use renamed test helpers and remove redundant private test-only helpers/locals.
- Updated ExtensionUIContext, InteractiveModeContext, and InteractiveMode to require editor factories to return CustomEditor instances.
- Removed the runtime compatibility guard and warning for non-CustomEditor implementations in setEditorComponent.
- Removed the test that verified rejection of non-CustomEditor factories in interactive-mode editor-component tests.
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