Add German audit_report.md for simdjson/jsoncons/blaze integrations

[Easton97-Jens]

Motivation

• Add a single, evidence-driven German audit combining Security, Correctness and Performance analyses for the JSON stack (simdjson, jsoncons, sourcemeta/blaze) as observed in the ModSecurity integration layers, and record gaps where upstream sources were not present.

Description

• Added audit_report.md containing Executive Summary, Methodik, per-project analyses (simdjson, jsoncons, Blaze), a findings table with concrete file/function references, analysis limits (missing submodules), and recommended next steps for fuzzing/differential testing and hardening.

Testing

• Documentation-only change; no production code was modified and no automated unit/integration tests were executed against this change (manual repository inspection and file creation were performed).

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Codex Task