Switch remote deploy to vendored source builds

Move remote deployment to a vendored source bundle built on the target host via Docker so redeploys no longer require local cross-compilation or host Go installation.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

vendor/github.com/wailsapp/wails/v2/pkg/menu/README.md

@@ -0,0 +1,10 @@
+# Menus
+
+Menu support is heavily inspired by Electron's approach.
+
+## Features
+
+  * Supports Text, Checkbox, Radio, Submenu and Separator
+  * Radio groups are defined as any number of adjacent radio items
+  * UTF-8 menu labels
+  * UTF-8 menu IDs