feat(ui): native vessel, HTML vessel update, native hello examples, profile card, UI tools

el-native vessel: El-level wrappers around __widget_* C builtins, exposing
vstack, label, button, text_field, etc. as clean El functions for application code.

el-html/main.elh: updated extern declarations for the HTML vessel's codegen API.

native-hello: cross-platform desktop example (AppKit/GTK4/Win32/SDL2) with
build scripts, Dockerfiles for Linux/Pi, and Win32 cross-compile support.

native-hello-android: Gradle project with ElBridge integration and build script.

native-hello-ios: Xcode project for the iOS UIKit target.

profile-card: manifest.el for a styling/layout/i18n example app that exercises
el-style, el-layout, el-i18n, el-config, and el-secrets vessels.

ui/tools/native-codegen: Python codegen pass (el_ui_native_codegen.py) that
lowers el-ui component DSL to el-native vessel calls, plus build script and
test fixtures.

ui/examples/native-hello-android/settings.gradle

@@ -0,0 +1,17 @@
+pluginManagement {
+    repositories {
+        google()
+        mavenCentral()
+        gradlePluginPortal()
+    }
+}
+dependencyResolutionManagement {
+    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
+    repositories {
+        google()
+        mavenCentral()
+    }
+}
+
+rootProject.name = "native-hello-android"
+include ':app'