reduce default visibility for new classes and packages

New visibilities:
- Java class -> package-private;
- Java record -> package-private;
- Kotlin class -> internal;
- package -> `@Internal`.

Interfaces and enums usually become API anyway, so they are kept public.

GitOrigin-RevId: d7451cd3f9b8340243bec929c6e98116db1b418b

.idea/fileTemplates/internal/Class.java

@@ -1,4 +1,4 @@
 #if (${PACKAGE_NAME} && ${PACKAGE_NAME} != "")package ${PACKAGE_NAME};#end
 #parse("File Header.java")
-public final class ${NAME} {
+final class ${NAME} {
 }

.idea/fileTemplates/internal/Kotlin Class.kt

@@ -0,0 +1,6 @@
+#if (${PACKAGE_NAME} && ${PACKAGE_NAME} != "")package ${PACKAGE_NAME}
+
+#end
+#parse("File Header.java")
+internal class ${NAME} {
+}

.idea/fileTemplates/internal/Record.java

@@ -0,0 +1,6 @@
+#if (${PACKAGE_NAME} && ${PACKAGE_NAME} != "")package ${PACKAGE_NAME};
+
+#end
+#parse("File Header.java")
+record ${NAME}() {
+}

.idea/fileTemplates/internal/package-info.java

@@ -0,0 +1,7 @@
+#parse("File Header.java")
+#if (${PACKAGE_NAME} && ${PACKAGE_NAME} != "")
+@Internal
+package ${PACKAGE_NAME};
+
+import org.jetbrains.annotations.ApiStatus.Internal;
+#end