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/profile-card/manifest.el

@@ -0,0 +1,25 @@
+package "profile-card" {
+    version "0.1.0"
+    description "el-ui profile card example — styling, layout, i18n, config, auth"
+    authors ["Neuron Technologies"]
+    edition "2026"
+}
+
+build {
+    entry "src/App.el"
+    target "debug"
+}
+
+dependencies {
+    el-style { path "../../vessels/el-style" }
+    el-layout { path "../../vessels/el-layout" }
+    el-i18n { path "../../vessels/el-i18n" }
+    el-config { path "../../vessels/el-config" }
+    el-secrets { path "../../vessels/el-secrets" }
+}
+
+app {
+    window_title "Profile Card"
+    window_width 800
+    window_height 600
+}