Fix baseline CI failures

[samuel-williams-shopify]

Summary

• raise the CMake minimum from 3.0 to 3.5 so current CMake 4 runners can configure the project
• update standalone inline-node rendering assertions to expect no trailing newline
• update CommonMark example 617 to reflect support for XML namespace prefixes in HTML tag names
• avoid an MSVC warnings-as-errors failure caused by shadowing the existing info variable in front matter rendering

These failures are already present on main and are unrelated to the inline-code-info feature.

Validation

• cmake -S . -B build-main-fix -DCMARK_SHARED=ON -DCMARK_STATIC=ON
• cmake --build build-main-fix --parallel
• ctest --test-dir build-main-fix --output-on-failure

All 13 CTest targets pass locally with CMake 4.1.1.