refactor: modularize codebase and add 404 unit tests

Split large files into focused modules across all crates while
maintaining API compatibility via re-exports. Add comprehensive
unit tests covering core models, pipeline parsers, LLM triage,
DAST security tools, graph algorithms, and MCP parameter validation.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

compliance-agent/src/api/routes.rs

@@ -136,7 +136,10 @@ pub fn build_router() -> Router {
             "/api/v1/pentest/sessions/{id}/export",
             post(handlers::pentest::export_session_report),
         )
-        .route("/api/v1/pentest/stats", get(handlers::pentest::pentest_stats))
+        .route(
+            "/api/v1/pentest/stats",
+            get(handlers::pentest::pentest_stats),
+        )
         // Webhook endpoints (proxied through dashboard)
         .route(
             "/webhook/github/{repo_id}",