[WIP] Issue #95 — Add a file to explain the design choices of the codebase

[leftibot]

Automated attempt by @leftibot. Opening as draft — verification failed.

Reason: no test files were detected in the diff

What changed

Fix #95: Add README_design.md documenting template design choices
New top-level doc explains the rationale behind the template's CMake
layout, C++23 default, warning/sanitizer/hardening flags, CPM-based
dependencies, dual top-level/subdir behavior, and the
myproject_ENABLE_* knobs. Wording is kept short and specific so
beginners and veterans can adapt the defaults knowingly.
Co-Authored-By: Claude Opus 4.7 (1M context) noreply@anthropic.com

Files

 README_design.md | 98 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 98 insertions(+)

Will close #95 once finalized.

Triggered by @lefticus.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 20.50%. Comparing base (ec01c73) to head (e067a22).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #154   +/-   ##
=======================================
  Coverage   20.50%   20.50%           
=======================================
  Files           5        5           
  Lines         239      239           
  Branches      111      110    -1     
=======================================
  Hits           49       49           
  Misses        186      186           
  Partials        4        4           

Flag	Coverage Δ
Linux	18.36% <ø> (ø)
Windows	21.02% <ø> (ø)
macOS	18.87% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.