test(19.3-05): build tags, S3 tag guard, DiskExtension and public_url

- manifest_tags_test.go: build.tags load, trim, dedupe and validation
  errors naming build.tags; SaveManifest keeps tags and plugin order;
  goBuildArgs puts one -tags before -o
- s3_test.go: s3:// refused without summercms_s3 naming the tag, opens
  with it (both build modes, any scheme case)
- diskext_test.go: RESEARCH probe rows and table consistency
- url_test.go: public_url base joining, File.URL and thumbnails,
  malformed values refused naming the key
- store_test.go: Postgres regression table through Store
- gate: attach names in both tag modes, Store regression in docker

scripts/check-phase19.3.sh

@@ -77,9 +77,25 @@ SURF_TESTS=(
 	TestAPIDocsTitleEscaped
 	TestBuildRouterStoreFallback TestBuildRouterUsesPublishedStore TestBuildRouterNeverDials
 )
+BUILD_TESTS=(
+	TestManifestBuildTags
+	TestManifestBuildTagsInvalid
+	TestSaveManifestKeepsBuildTags
+	TestGoBuildArgs
+)
+# The attach names run twice: untagged and with -tags summercms_s3.
+ATTACH_TESTS=(
+	TestOpenBucketS3
+	TestDiskExtensionTable
+	TestPublicURLBase
+	TestPublicURLValidation
+)
 
 # docker stage: testcontainers suites.
 DOCKER_CABANA_TESTS=(TestReorderHookRunsInTx TestReorderHookErrorRollsBack TestReorderWithoutHookUnchanged)
+DOCKER_ATTACH_TESTS=(
+	TestStoreDiskExtension
+)
 
 usage() {
 	cat >&2 <<'EOF'
@@ -344,6 +360,9 @@ run_go() {
 	go_short "$ROOT"
 	go_named "$ROOT" ./modules/bouncer -short "${BOUNCER_TESTS[@]}"
 	go_named "$ROOT" ./modules/surf -short "${SURF_TESTS[@]}"
+	go_named "$ROOT" ./internal/build -short "${BUILD_TESTS[@]}"
+	go_named "$ROOT" ./modules/lagoon/attach -short "${ATTACH_TESTS[@]}"
+	go_named "$ROOT" ./modules/lagoon/attach "-short -tags summercms_s3" "${ATTACH_TESTS[@]}"
 	echo "phase19.3 go passed"
 }
 
@@ -357,6 +376,7 @@ run_docker() {
 		return 1
 	fi
 	go_named "$ROOT" ./modules/cabana "-timeout 20m" "${DOCKER_CABANA_TESTS[@]}"
+	go_named "$ROOT" ./modules/lagoon/attach "-timeout 20m" "${DOCKER_ATTACH_TESTS[@]}"
 	echo "phase19.3 docker passed"
 }