Remove the obsolete scan setup widget

[ianw-oai]

Summary

• Remove the old HTML setup widget and its unused tools.
• Start standard, changes, and deep scans through existing native tools.
• Keep public fixes for scan recovery, file safety, finding identity, and user context.

Tests

• Type checks, formatting, and build passed.
• 226 SDK tests passed; seven Windows-only tests were skipped.
• The packed and installed npm package passed public import, CLI, plugin, and nested worker checks.