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/metrics-and-slos.md

@@ -1,6 +1,6 @@
 # Metrics & SLOs (DOCS-OBS-51-001)
 
-Last updated: 2025-11-25 (Docs Tasks Md.VI)
+Last updated: 2025-12-15
 
 ## Core metrics (platform-wide)
 - **Requests**: `http_requests_total{tenant,workload,route,status}` (counter); latency histogram `http_request_duration_seconds`.
@@ -24,6 +24,77 @@ Last updated: 2025-11-25 (Docs Tasks Md.VI)
 - Queue backlog: `queue_depth > 1000` for 5m.
 - Job failures: `rate(worker_jobs_total{status="failed"}[10m]) > 0.01`.
 
+## UX KPIs (triage TTFS)
+- Targets:
+  - TTFS first evidence p95: <= 1.5s
+  - TTFS skeleton p95: <= 0.2s
+  - Clicks-to-closure median: <= 6
+  - Evidence completeness avg: >= 90% (>= 3.6/4)
+
+```promql
+# TTFS first evidence p50/p95
+histogram_quantile(0.50, sum(rate(stellaops_ttfs_first_evidence_seconds_bucket[5m])) by (le))
+histogram_quantile(0.95, sum(rate(stellaops_ttfs_first_evidence_seconds_bucket[5m])) by (le))
+
+# Clicks-to-closure median
+histogram_quantile(0.50, sum(rate(stellaops_clicks_to_closure_bucket[5m])) by (le))
+
+# Evidence completeness average percent (0-4 mapped to 0-100)
+100 * (sum(rate(stellaops_evidence_completeness_score_sum[5m])) / clamp_min(sum(rate(stellaops_evidence_completeness_score_count[5m])), 1)) / 4
+
+# Budget violations by phase
+sum(rate(stellaops_performance_budget_violations_total[5m])) by (phase)
+```
+
+- Dashboard: `ops/devops/observability/grafana/triage-ttfs.json`
+- Alerts: `ops/devops/observability/triage-alerts.yaml`
+
+## TTFS Metrics (time-to-first-signal)
+- Core metrics:
+  - `ttfs_latency_seconds{surface,cache_hit,signal_source,kind,phase,tenant_id}` (histogram)
+  - `ttfs_signal_total{surface,cache_hit,signal_source,kind,phase,tenant_id}` (counter)
+  - `ttfs_cache_hit_total{surface,cache_hit,signal_source,kind,phase,tenant_id}` (counter)
+  - `ttfs_cache_miss_total{surface,cache_hit,signal_source,kind,phase,tenant_id}` (counter)
+  - `ttfs_slo_breach_total{surface,cache_hit,signal_source,kind,phase,tenant_id}` (counter)
+  - `ttfs_error_total{surface,cache_hit,signal_source,kind,phase,tenant_id,error_type,error_code}` (counter)
+
+- SLO targets:
+  - P50 < 2s, P95 < 5s (all surfaces)
+  - Warm path P50 < 700ms, P95 < 2.5s
+  - Cold path P95 < 4s
+
+```promql
+# TTFS latency p50/p95
+histogram_quantile(0.50, sum(rate(ttfs_latency_seconds_bucket[5m])) by (le))
+histogram_quantile(0.95, sum(rate(ttfs_latency_seconds_bucket[5m])) by (le))
+
+# SLO breach rate (per minute)
+60 * sum(rate(ttfs_slo_breach_total[5m]))
+```
+
+## Offline Kit (air-gap) metrics
+- `offlinekit_import_total{status,tenant_id}` (counter)
+- `offlinekit_attestation_verify_latency_seconds{attestation_type,success}` (histogram)
+- `attestor_rekor_success_total{mode}` (counter)
+- `attestor_rekor_retry_total{reason}` (counter)
+- `rekor_inclusion_latency{success}` (histogram)
+
+```promql
+# Import rate by status
+sum(rate(offlinekit_import_total[5m])) by (status)
+
+# Import success rate
+sum(rate(offlinekit_import_total{status="success"}[5m])) / clamp_min(sum(rate(offlinekit_import_total[5m])), 1)
+
+# Attestation verify p95 by type (success only)
+histogram_quantile(0.95, sum(rate(offlinekit_attestation_verify_latency_seconds_bucket{success="true"}[5m])) by (le, attestation_type))
+
+# Rekor inclusion latency p95 (by success)
+histogram_quantile(0.95, sum(rate(rekor_inclusion_latency_bucket[5m])) by (le, success))
+```
+
+Dashboard: `docs/observability/dashboards/offline-kit-operations.json`
+
 ## Observability hygiene
 - Tag everything with `tenant`, `workload`, `env`, `region`, `version`.
 - Keep metric names stable; prefer adding labels over renaming.