Add call graph fixtures for various languages and scenarios

- Introduced `all-edge-reasons.json` to test edge resolution reasons in .NET.
- Added `all-visibility-levels.json` to validate method visibility levels in .NET.
- Created `dotnet-aspnetcore-minimal.json` for a minimal ASP.NET Core application.
- Included `go-gin-api.json` for a Go Gin API application structure.
- Added `java-spring-boot.json` for the Spring PetClinic application in Java.
- Introduced `legacy-no-schema.json` for legacy application structure without schema.
- Created `node-express-api.json` for an Express.js API application structure.

docs/observability/dashboards/offline-kit-operations.json

@@ -0,0 +1,76 @@
+{
+  "schemaVersion": 39,
+  "title": "Offline Kit Operations",
+  "panels": [
+    {
+      "type": "timeseries",
+      "title": "Offline Kit imports by status (rate)",
+      "datasource": "Prometheus",
+      "fieldConfig": { "defaults": { "unit": "ops", "decimals": 3 } },
+      "targets": [
+        { "expr": "sum(rate(offlinekit_import_total[5m])) by (status)", "legendFormat": "{{status}}" }
+      ]
+    },
+    {
+      "type": "stat",
+      "title": "Offline Kit import success rate (%)",
+      "datasource": "Prometheus",
+      "fieldConfig": { "defaults": { "unit": "percent", "decimals": 2 } },
+      "targets": [
+        {
+          "expr": "100 * sum(rate(offlinekit_import_total{status=\"success\"}[5m])) / clamp_min(sum(rate(offlinekit_import_total[5m])), 1)"
+        }
+      ]
+    },
+    {
+      "type": "timeseries",
+      "title": "Attestation verify latency p50/p95 (success)",
+      "datasource": "Prometheus",
+      "fieldConfig": { "defaults": { "unit": "s", "decimals": 3 } },
+      "targets": [
+        {
+          "expr": "histogram_quantile(0.50, sum(rate(offlinekit_attestation_verify_latency_seconds_bucket{success=\"true\"}[5m])) by (le, attestation_type))",
+          "legendFormat": "p50 {{attestation_type}}"
+        },
+        {
+          "expr": "histogram_quantile(0.95, sum(rate(offlinekit_attestation_verify_latency_seconds_bucket{success=\"true\"}[5m])) by (le, attestation_type))",
+          "legendFormat": "p95 {{attestation_type}}"
+        }
+      ]
+    },
+    {
+      "type": "timeseries",
+      "title": "Rekor inclusion latency p50/p95 (by success)",
+      "datasource": "Prometheus",
+      "fieldConfig": { "defaults": { "unit": "s", "decimals": 3 } },
+      "targets": [
+        {
+          "expr": "histogram_quantile(0.50, sum(rate(rekor_inclusion_latency_bucket[5m])) by (le, success))",
+          "legendFormat": "p50 success={{success}}"
+        },
+        {
+          "expr": "histogram_quantile(0.95, sum(rate(rekor_inclusion_latency_bucket[5m])) by (le, success))",
+          "legendFormat": "p95 success={{success}}"
+        }
+      ]
+    },
+    {
+      "type": "timeseries",
+      "title": "Rekor verification successes (rate)",
+      "datasource": "Prometheus",
+      "fieldConfig": { "defaults": { "unit": "ops", "decimals": 3 } },
+      "targets": [
+        { "expr": "sum(rate(attestor_rekor_success_total[5m])) by (mode)", "legendFormat": "{{mode}}" }
+      ]
+    },
+    {
+      "type": "timeseries",
+      "title": "Rekor verification retries (rate)",
+      "datasource": "Prometheus",
+      "fieldConfig": { "defaults": { "unit": "ops", "decimals": 3 } },
+      "targets": [
+        { "expr": "sum(rate(attestor_rekor_retry_total[5m])) by (reason)", "legendFormat": "{{reason}}" }
+      ]
+    }
+  ]
+}