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/labstack/echo/v4/renderer.go

@@ -0,0 +1,29 @@
+package echo
+
+import "io"
+
+// Renderer is the interface that wraps the Render function.
+type Renderer interface {
+	Render(io.Writer, string, interface{}, Context) error
+}
+
+// TemplateRenderer is helper to ease creating renderers for `html/template` and `text/template` packages.
+// Example usage:
+//
+//		e.Renderer = &echo.TemplateRenderer{
+//			Template: template.Must(template.ParseGlob("templates/*.html")),
+//		}
+//
+//	  e.Renderer = &echo.TemplateRenderer{
+//			Template: template.Must(template.New("hello").Parse("Hello, {{.}}!")),
+//		}
+type TemplateRenderer struct {
+	Template interface {
+		ExecuteTemplate(wr io.Writer, name string, data any) error
+	}
+}
+
+// Render renders the template with given data.
+func (t *TemplateRenderer) Render(w io.Writer, name string, data interface{}, c Context) error {
+	return t.Template.ExecuteTemplate(w, name, data)
+}