feat: add E2E test suite with nightly CI, fix dashboard Dockerfile

E2E Tests:
- 17 integration tests covering: health, repos CRUD, findings lifecycle,
  cascade delete (SAST + DAST + pentest), DAST targets, stats overview
- TestServer harness: spins up agent API on random port with isolated
  MongoDB database per test, auto-cleanup
- Added lib.rs to expose agent internals for integration tests
- Nightly CI workflow with MongoDB service container (3 AM UTC)

Tests verify:
- Repository add/list/delete + duplicate rejection + invalid ID handling
- Finding creation, filtering by severity/repo, status updates, bulk updates
- Cascade delete: repo deletion removes all DAST targets, pentest sessions,
  attack chain nodes, DAST findings, SAST findings, and SBOM entries
- DAST target CRUD and empty finding list
- Stats overview accuracy with zero and populated data

Also:
- Fix Dockerfile.dashboard: bump dioxus-cli 0.7.3 → 0.7.4 (compile fix)
- Fix clippy: allow new_without_default for pattern scanners

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

compliance-agent/tests/integration/api/dast.rs

@@ -0,0 +1,48 @@
+use crate::common::TestServer;
+use serde_json::json;
+
+#[tokio::test]
+async fn add_and_list_dast_targets() {
+    let server = TestServer::start().await;
+
+    // Initially empty
+    let resp = server.get("/api/v1/dast/targets").await;
+    assert_eq!(resp.status(), 200);
+    let body: serde_json::Value = resp.json().await.unwrap();
+    assert_eq!(body["data"].as_array().unwrap().len(), 0);
+
+    // Add a target
+    let resp = server
+        .post(
+            "/api/v1/dast/targets",
+            &json!({
+                "name": "test-app",
+                "base_url": "https://test-app.example.com",
+                "target_type": "webapp",
+            }),
+        )
+        .await;
+    assert_eq!(resp.status(), 200);
+
+    // List should return 1
+    let resp = server.get("/api/v1/dast/targets").await;
+    let body: serde_json::Value = resp.json().await.unwrap();
+    let targets = body["data"].as_array().unwrap();
+    assert_eq!(targets.len(), 1);
+    assert_eq!(targets[0]["name"], "test-app");
+    assert_eq!(targets[0]["base_url"], "https://test-app.example.com");
+
+    server.cleanup().await;
+}
+
+#[tokio::test]
+async fn list_dast_findings_empty() {
+    let server = TestServer::start().await;
+
+    let resp = server.get("/api/v1/dast/findings").await;
+    assert_eq!(resp.status(), 200);
+    let body: serde_json::Value = resp.json().await.unwrap();
+    assert_eq!(body["data"].as_array().unwrap().len(), 0);
+
+    server.cleanup().await;
+}