fix(ci): security toggles tests, CrowdSec response data, and coverage improvement documentation

- Implemented comprehensive tests for security toggle handlers in `security_toggles_test.go`, covering enable/disable functionality for ACL, WAF, Cerberus, CrowdSec, and RateLimit.
- Added sample JSON response for CrowdSec decisions in `lapi_decisions_response.json`.
- Created aggressive preset configuration for CrowdSec in `preset_aggressive.json`.
- Documented backend coverage, security fixes, and E2E testing improvements in `2026-02-02_backend_coverage_security_fix.md`.
- Developed a detailed backend test coverage restoration plan in `current_spec.md` to address existing gaps and improve overall test coverage to 86%+.

backend/internal/testdata/handlers/crowdsec/lapi_decisions_response.json

@@ -0,0 +1,13 @@
+[
+  {
+    "id": 1,
+    "origin": "crowdsec",
+    "type": "ban",
+    "scope": "ip",
+    "value": "192.168.1.100",
+    "duration": "4h",
+    "scenario": "crowdsecurity/http-probing",
+    "created_at": "2024-01-01T12:00:00Z",
+    "until": "2024-01-01T16:00:00Z"
+  }
+]