dispatch: allow empty route kinds (match all) + add routing tests

- config: permit routes[].kinds to be omitted/empty; treat as "all kinds"
- dispatch: compile empty kinds to Route{Kinds:nil} (match all kinds)
- tests: add coverage for route compilation + config validation edge cases

Files:
- config/load.go
- config/config.go
- dispatch/routes.go
- config/validate_test.go
- dispatch/routes_test.go

config/validate_test.go

@@ -0,0 +1,48 @@
+package config
+
+import (
+	"strings"
+	"testing"
+	"time"
+)
+
+func TestValidate_RouteKindsEmptyIsAllowed(t *testing.T) {
+	cfg := &Config{
+		Sources: []SourceConfig{
+			{Name: "src1", Driver: "driver1", Every: Duration{Duration: time.Minute}},
+		},
+		Sinks: []SinkConfig{
+			{Name: "sink1", Driver: "stdout"},
+		},
+		Routes: []RouteConfig{
+			{Sink: "sink1", Kinds: nil},        // omitted
+			{Sink: "sink1", Kinds: []string{}}, // explicit empty
+		},
+	}
+
+	if err := cfg.Validate(); err != nil {
+		t.Fatalf("expected no error, got: %v", err)
+	}
+}
+
+func TestValidate_RouteKindsRejectsBlankEntries(t *testing.T) {
+	cfg := &Config{
+		Sources: []SourceConfig{
+			{Name: "src1", Driver: "driver1", Every: Duration{Duration: time.Minute}},
+		},
+		Sinks: []SinkConfig{
+			{Name: "sink1", Driver: "stdout"},
+		},
+		Routes: []RouteConfig{
+			{Sink: "sink1", Kinds: []string{"observation", "   ", "alert"}},
+		},
+	}
+
+	err := cfg.Validate()
+	if err == nil {
+		t.Fatalf("expected error, got nil")
+	}
+	if !strings.Contains(err.Error(), "routes[0].kinds[1]") {
+		t.Fatalf("expected error to mention blank kind entry, got: %v", err)
+	}
+}