Refactor Riemannian Util layout and simp helpers (#5 #6 #7)

[poet77]

Summary

• Implements Reorganize Riemannian/Util/ into themed sub-directories #5 by moving OpenGALib/Riemannian/Util into themed subdirectories.
• Implements Rename ChartJacobianSmooth / ChartJacobianSmoothness for clarity #7 by renaming the chart-Jacobian modules to ChartJacobianCLM / ChartJacobianEntries.
• Implements Merge small Util files: OperatorSimp + CovDeriv consolidation #6 by merging ConnectionLaplacianSimp.lean and DivergenceSimp.lean into Util/Simp/OperatorSimp.lean.
• Retargets the closed PR Refactor Riemannian Util layout and simp helpers (#5 #6 #7) #41 work onto main after the explicit-g cascade landed.

Issue Links

Closes #5.
Closes #6.
Closes #7.

Rebase Notes

• Carries over the 9k: eliminate _g wrappers — Bochner stack fully explicit-g #47 semantic change in OperatorSimp.lean: connectionLaplacian_def unfolds through smoothOrthoFrame g, not smoothOrthoFrame hm.metric.
• Keeps Bochner touched files to import-path updates only; no deleted _g wrappers are reintroduced.
• Follow-up PR [Depends on #41] Reduce strict defeq compatibility options (#8) #43 / Eliminate set_option backward.isDefEq.respectTransparency false workarounds #8 remains separate.

Validation

• git diff --check origin/main..develop
• lake env lean OpenGALib/Riemannian/Util/Simp/OperatorSimp.lean
• lake build