fix: Fix a rounding error at the Number::maxRep cusp

[ximinez]

High Level Overview of Change

If the mantissa result of an operation is maxRep, and should round up, it rounds down instead.

Context of Change

API Impact

[github-actions]

This PR has conflicts, please resolve them in order for the PR to be reviewed.

[godexsoft]

We recently merged a refactor to develop that enables clang-tidy's readability-identifier-naming. Your branch now has heavy conflicts that are largely mechanical. Below is a workflow that aligns your branch's naming with develop before merging, which should minimize the merge conflicts.

One-time setup

If you don't already have clang-tidy working in your env, on macOS:

brew install llvm@21
# Follow brew's hint to put $(brew --prefix llvm@21)/bin on PATH so run-clang-tidy is found.

Workflow on your branch (before merging develop)

1. Grab the new .clang-tidy from develop without pulling anything else. Sync your fork on GitHub first, then:

git remote -v   # should show 'upstream' among others; if not:
# git remote set-url upstream git@github.com:XRPLF/rippled.git
git fetch upstream
git checkout upstream/develop -- .clang-tidy

2. Reconfigure conan/cmake so compile_commands.json is fresh.

3. Apply renames for the files modified in your PR:

git diff --name-only $(git merge-base HEAD upstream/develop) HEAD \
  | grep -E '\.(cpp|h|hpp|ipp)$' \
  | xargs run-clang-tidy -p build -fix -allow-no-checks
# or -p .build, or whatever your build dir is called

4. Build + test, then commit as a single dedicated commit:

cmake --build build -j8
git commit -am "refactor: Align identifier naming with develop"

5. Now merge develop:

git merge upstream/develop

Extra

Run clang-tidy once more after the merge to catch any stragglers introduced from develop's side:

run-clang-tidy -p build -fix -allow-no-checks src tests
# or -p .build, or whatever your build dir is called