[Elvand-Lie]

This Pull request:

Changes or fixes:

TProfile::Scale, TProfile2D::Scale, and TProfile3D::Scale leave the cached statistics of the profiled value unchanged. They also leave buffered fills unscaled.

TProfile p("p", "", 10, 0, 10);
p.Fill(1, 2); p.Fill(2, 4);
p.Scale(3);
// Before: bin content 12, mean 3, standard deviation 1
// After:  bin content 12, mean 9, standard deviation 3

Flush pending fills before scaling and scale the corresponding first and second moments by the factor and its square. Regression tests cover all three profile dimensions and buffered fills.

The four regression tests fail on the base and pass with the fix. The full test_TProfile executable passes (8 tests) on Linux. The full ROOT test suite and other platforms were not run.

Checklist:

• tested changes locally
• updated the docs (if necessary)

Codex (gpt-6.1-terra) implemented the fix and the test; Claude Code (claude-opus-5-5) found the bug.