Add comprehensive security tests for OWASP A03 (Injection) and A10 (SSRF)

- Implemented InjectionTests.cs to cover various injection vulnerabilities including SQL, NoSQL, Command, LDAP, and XPath injections.
- Created SsrfTests.cs to test for Server-Side Request Forgery (SSRF) vulnerabilities, including internal URL access, cloud metadata access, and URL allowlist bypass attempts.
- Introduced MaliciousPayloads.cs to store a collection of malicious payloads for testing various security vulnerabilities.
- Added SecurityAssertions.cs for common security-specific assertion helpers.
- Established SecurityTestBase.cs as a base class for security tests, providing common infrastructure and mocking utilities.
- Configured the test project StellaOps.Security.Tests.csproj with necessary dependencies for testing.

bench/baselines/ttfs-baseline.json

@@ -0,0 +1,56 @@
+{
+  "$schema": "https://json-schema.org/draft-07/schema#",
+  "title": "TTFS Baseline",
+  "description": "Time-to-First-Signal baseline metrics for regression detection",
+  "version": "1.0.0",
+  "created_at": "2025-12-16T00:00:00Z",
+  "updated_at": "2025-12-16T00:00:00Z",
+  "metrics": {
+    "ttfs_ms": {
+      "p50": 1500,
+      "p95": 4000,
+      "p99": 6000,
+      "min": 500,
+      "max": 10000,
+      "mean": 2000,
+      "sample_count": 500
+    },
+    "by_scan_type": {
+      "image_scan": {
+        "p50": 2500,
+        "p95": 5000,
+        "p99": 7500,
+        "description": "Container image scanning TTFS baseline"
+      },
+      "filesystem_scan": {
+        "p50": 1000,
+        "p95": 2000,
+        "p99": 3000,
+        "description": "Filesystem/directory scanning TTFS baseline"
+      },
+      "sbom_scan": {
+        "p50": 400,
+        "p95": 800,
+        "p99": 1200,
+        "description": "SBOM-only scanning TTFS baseline"
+      }
+    }
+  },
+  "thresholds": {
+    "p50_max_ms": 2000,
+    "p95_max_ms": 5000,
+    "p99_max_ms": 8000,
+    "max_regression_pct": 10,
+    "description": "Thresholds that will trigger CI gate failures"
+  },
+  "collection_info": {
+    "test_environment": "ci-standard-runner",
+    "runner_specs": {
+      "cpu_cores": 4,
+      "memory_gb": 8,
+      "storage_type": "ssd"
+    },
+    "sample_corpus": "tests/reachability/corpus",
+    "collection_window_days": 30
+  }
+}