Add core components for JSON anomaly detection including:

• StreamParser for continuous JSON parsing from stdin/files
• AnomalyDetector with threshold, z-score and frequency rules
• Main application with CLI options for configuration
• CMake build system configuration
• Unit test scaffolding

The detector processes JSON streams in real-time, applies detection rules, and generates alerts for anomalies. Supports following files (tail -f mode) and benchmarking.

Short title (summary):

Description

• What did you change and why? (1-3 sentences)
• Issue reproduced / related issue: link the issue if relevant (e.g. Fix typo in title #123)

Type of change

• Bug fix
• Optimization
• New feature
• Refactor / cleanup
• Documentation / tests
• Other (please describe):

How to verify / test

• Add additional tests to verify bugs or new features.
• If you claim performance gains, you should provide benchmark numbers using high quality benchmarking code.

Please read before contributing:

• CONTRIBUTING: https://github.com/simdjson/simdjson/blob/master/CONTRIBUTING.md
• HACKING: https://github.com/simdjson/simdjson/blob/master/HACKING.md

If you can, we recommend running our tests with the sanitizers turned on.
For non-Visual Studio users, it is as easy as doing:

cmake -B build -D SIMDJSON_SANITIZE=ON -D SIMDJSON_DEVELOPER_MODE=ON
cmake --build build
ctest --test-dir build

Our CI checks, among other things, for trailing whitespace. If a test fails for that reason,
use the "artifacts" button to download the artifact and inspect the problematic lines,
or run scripts/remove_trailing_whitespace.sh locally if you have a bash shell and sed.

Checklist before submitting

• I added/updated tests covering my change (if applicable)
• Code builds locally and passes my check
• Documentation / README updated if needed
• Commits are atomic and messages are clear
• I linked the related issue (if applicable)

Final notes

• For large PRs, prefer smaller incremental PRs or request staged review.

Thanks for the contribution!