feat(13-04): wire all 12 Phase 13 sources into RegisterAll (40 total)

- Add 8 package registry sources (npm, pypi, crates, rubygems, maven, nuget, goproxy, packagist)
- Update register_test to assert 40 sources in sorted list
- Update Phase 12 integration test count from 32 to 40

pkg/recon/sources/integration_test.go

@@ -524,8 +524,8 @@ func TestRegisterAll_Phase12(t *testing.T) {
 	})
 
 	names := eng.List()
-	if n := len(names); n != 32 {
-		t.Fatalf("expected 32 sources from RegisterAll, got %d: %v", n, names)
+	if n := len(names); n != 40 {
+		t.Fatalf("expected 40 sources from RegisterAll, got %d: %v", n, names)
 	}
 
 	// Build lookup for source access.