Add Sonar + architecture re-analysis report for PR #3540

[Easton97-Jens]

Motivation

• Provide a fresh, evidence-based SonarCloud and architecture re-analysis for PR Prototype 2: Evaluating alternatives to YAJL for JSON processing owasp-modsecurity/ModSecurity#3540 that enumerates current findings and documents limits.
• Deliver a focused inspection of the JSON backend area and repository build-time backend selection to inform review and remediation prioritization.

Description

• Added a new analysis document analysis_pr3540_sonar_architektur.md containing the PR metadata, Sonar quality gate table, measures, a fully enumerated findings table (issues + gate conditions + hotspots), and a separate open-findings table.
• Included a focused section that lists findings for the requested JSON files and suggests minimal technical fixes for each open issue in those files.
• Performed a code-facts architecture assessment showing build-time backend selection via configure.ac, selective backend compilation in src/Makefile.am and build/win32/CMakeLists.txt, and the shared interface/adapter (files such as src/request_body_processor/json_backend.h and src/request_body_processor/json_adapter.cc).
• Documented analysis limits and completeness statements (which Sonar APIs were reachable and which data elements are not directly verifiable from the current sources).

Testing

• Queried GitHub PR metadata with curl against the GitHub API to verify PR presence and metadata (successful).
• Queried SonarCloud endpoints with curl for pull request list, qualitygates/project_status, measures/component, issues/search and hotspots/search and verified responses including issues total (214) and hotspots (0).
• Ran the local Python assembly script to convert fetched Sonar/GitHub responses into the report file analysis_pr3540_sonar_architektur.md (file produced successfully).
• Verified the report file exists in the repository working tree and is included as a new file.

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Codex Task