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/internal/goversion/build_constraint.go

@@ -0,0 +1,10 @@
+//go:build !go1.18
+// +build !go1.18
+
+package goversion
+
+const MinGoVersionRequired = "You need Go " + MinRequirement + " or newer to compile this program"
+
+func init() {
+	MinGoVersionRequired
+}

vendor/github.com/wailsapp/wails/v2/internal/goversion/min.go

@@ -0,0 +1,3 @@
+package goversion
+
+const MinRequirement string = "1.20"