fix(tests): tolerate CRLF working-tree line endings in freshness and style gates

[tahayusab]

On Windows checkouts (autocrlf), three gates compare raw bytes against
line-ending-sensitive patterns and fail spuriously:

$ bun test src/__tests__/architecture/plugin-bootstrap-fresh.test.ts
(fail) generated plugin bootstrap artifacts > match a fresh bundle of
      bootstrap/src/ (run `bun run bootstrap:sync` if this fails)

Root causes:

• scripts/sync-plugin-bootstrap.ts bundles from on-disk sources; on a CRLF
  working tree the CRLFs are carried into the bundle and JSON-escaped, so the
  in-memory artifact diverges from the committed (LF) artifact even with no
  source drift.
• plugin-bootstrap-fresh.test.ts compares the committed artifact
  byte-for-byte; a CRLF-checked-out file never equals the LF string.
• siteExplorerPanel.test.tsx matches a multi-line CSS selector block with a
  regex that hardcodes \n line breaks.

Changes:

• Normalize the bundled text to LF in bundleEntry so emitted artifacts stay
  platform-independent (no-op on LF checkouts; committed artifacts unchanged).
• EOL-normalize the file read in the freshness gate.
• Make the CSS block regex use \r?\n.

Verified on a Windows / autocrlf checkout: plugin-bootstrap-fresh 1 pass,
siteExplorerPanel 40/40 pass (was 39 + 1 fail), no prior bootstrap:sync,
git status clean on generated/. bun run build + bun run lint green.