feat: add Temporal config and update routing with memory service integration

- Add TemporalConfig struct to internal/config
- Update gateway config with Temporal frontend service (port 7233)
- Update router with memory service adapter support
- Add config.local.yaml with memory service configuration
- Encrypt production config with SOPS (AES256_GCM)
- Support X-Service header routing pattern for service discovery
- Keep legacy path-based routes with deprecation warnings
- All 5 adapters preserved: workflow, memory, sqs, s3, iam

internal/server/router.go

@@ -33,8 +33,8 @@ func NewRouter(healthChecker *HealthChecker, dispatcher *serviceadapter.Dispatch
 // ServeHTTP implements http.Handler.
 // Priority order:
 // 1. /healthz and /readyz to health handlers
-// 2. X-Service header to ServiceAdapter dispatcher (phase 8)
-// 3. /workflow* to temporal handler
+// 2. X-Service header to ServiceAdapter dispatcher (phase 8) - PREFERRED routing method
+// 3. /workflow* to temporal handler - DEPRECATED: use X-Service: workflow instead
 // 4. All other paths to upstream handler (phase 0-7)
 func (r *Router) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 	// Health endpoints first
@@ -48,6 +48,8 @@ func (r *Router) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 	}
 
 	// X-Service (ServiceAdapter) routing - checked before path-based routing
+	// PREFERRED: All service routing should use X-Service header pattern for consistency,
+	// auth enforcement, and resource-based access control.
 	if req.Header.Get("X-Service") != "" {
 		if r.dispatcher != nil {
 			r.dispatcher.Dispatch(w, req)
@@ -56,6 +58,8 @@ func (r *Router) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 	}
 
 	// Workflow endpoints
+	// DEPRECATED: Path-based /workflow routing is legacy.
+	// New clients should use X-Service: workflow header instead for consistent auth.
 	switch req.URL.Path {
 	case "/workflow", "/workflow/health", "/workflow/metrics":
 		r.temporalHandler.ServeHTTP(w, req)