semi implemented and features implemented save checkpoint

docs/features/unchecked/scanner/api-gateway-boundary-extractor.md

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+# API Gateway Boundary Extractor (Kong, Envoy/Istio, AWS API Gateway, Traefik)
+
+## Module
+Scanner
+
+## Status
+IMPLEMENTED
+
+## Description
+Parses API gateway configurations from Kong, Envoy/Istio, AWS API Gateway, and Traefik to extract route-level boundary information for reachability analysis. Determines which internal services are exposed through gateway routes.
+
+## Implementation Details
+- **Core Extractor**:
+  - `src/Scanner/__Libraries/StellaOps.Scanner.Reachability/Boundary/GatewayBoundaryExtractor.cs` - `GatewayBoundaryExtractor` implements `IBoundaryProofExtractor`; parses Kong, Envoy/Istio, AWS API Gateway, and Traefik configurations
+  - Includes gateway-specific auth detection: `DetectKongAuth()`, `DetectEnvoyAuth()` (including Istio JWT/AuthorizationPolicy), `DetectTraefikAuth()`
+  - Identifies Istio mesh internal routes and external ingress routes
+- **Supporting Infrastructure**:
+  - `src/Scanner/__Libraries/StellaOps.Scanner.Reachability/Boundary/IacBoundaryExtractor.cs` - Infrastructure-as-code boundary extraction
+  - `src/Scanner/__Libraries/StellaOps.Scanner.Reachability/Boundary/BoundaryServiceCollectionExtensions.cs` - DI registration for boundary extractors
+  - `src/Scanner/__Libraries/StellaOps.Scanner.Reachability/Boundary/BoundaryExtractionContext.cs` - Context model for boundary extraction
+  - `src/Scanner/__Libraries/StellaOps.Scanner.Reachability/Boundary/RichGraphBoundaryExtractor.cs` - Integrates boundary data into rich graphs
+- **Tests**:
+  - `src/Scanner/__Tests/StellaOps.Scanner.Reachability.Tests/GatewayBoundaryExtractorTests.cs`
+
+## E2E Test Plan
+- [ ] Provide a Kong configuration file with routes exposing internal services and verify extracted boundary information includes route paths, upstream services, and auth requirements
+- [ ] Provide an Envoy/Istio configuration with VirtualService and AuthorizationPolicy and verify correct route-to-service mappings and auth detection
+- [ ] Provide an AWS API Gateway configuration and verify correct extraction of REST/HTTP API routes with Lambda/ECS integrations
+- [ ] Provide a Traefik configuration with middleware auth and verify correct route extraction with authentication metadata
+- [ ] Verify extracted boundaries are reflected in the reachability rich graph via `GET /api/v1/scans/{scanId}/reachability`
+- [ ] Verify that gated gateway routes (auth-required) reduce reachability risk scores compared to ungated routes