fix: preserve authored casing in note suites

[utensil]

Scope

Restores the convention for the requested recursive note suites:

• Capitalize actual section titles.
• Preserve exact authored casing for taxon-card titles, including intentional forms such as SDFs and intentionally lowercase definitions.

The patch restores 17 AG card/reference-definition titles from the earlier blanket title-casing change, then capitalizes the only additional true section titles found in the full suite audit:

• CA: Basics: from groups to modules, Algebras
• UTS: Disclaimer, Editorial remarks

tt-0001 and spin-0001 were audited recursively and require no source edit.

Validation

• CI=1 ./chk.sh
• just build
• just verify-render — 1,222 XML/HTML page pairs
• just verify-pdf-fixtures — all seven fixtures
• Local browser readback of AG, TT, CA, Spin, and UTS: intended visible casing and no captured runtime errors

Gate

Human-gated PR: please review and merge manually if accepted. No automatic merge or deployment is requested.