Add parser: JSONpp (C++17 header-only library)

[mikami-w]

Description

Adds a parser adapter for JSONpp (v0.1.1).

Repository: https://github.com/mikami-w/jsonpp

Implementation Details

• Auto-build: A build.sh script is provided to automate dependency fetching and building.
• Source Management: The script downloads the source code from the v0.1.1 release tag; source code is NOT included in this PR.

How to build

cd parsers/test_jsonpp_0_1_1
chmod +x build.sh
./build.sh
# Binary will be generated at: parsers/test_jsonpp_0_1_1/bin/test_jsonpp

Compliance Notes

The library passes all y_ tests. Some number formatting edge cases in n_ tests are accepted by design.