Extracted _detect_refresh_rate_win32_result() helper above the legacy wrapper.
ANTI-SLIMING: full Result[T] propagation (NO narrowing+logging). The helper
returns Result(data=rate) on success or Result(data=0.0, errors=[ErrorInfo])
on exception (logging NOT a drain per the user's principle 2026-06-17).
The legacy _detect_refresh_rate_win32() wrapper preserves its signature and
delegates to the helper. The call site in App.__init__ invokes the result
helper directly and drains errors to self._startup_timeline_errors.
Tests: 2 new tests (test_phase_10_l216_detect_refresh_rate_win32_result_success,
test_phase_10_l216_detect_refresh_rate_win32_result_failure) verify both paths.
Audit: L216 reclassified from INTERNAL_SILENT_SWALLOW (12 sites remaining,
was 13). New helper L219 is INTERNAL_COMPLIANT.
ed