fix double error rendering

cmd/astrolabe/handlers.go

···
 	}
 	resp, err := RepoGetRecord(ctx, &xrpcc, "", collection.String(), ident.DID.String(), rkey.String())
 	if err != nil {
-		return err
+		return echo.NewHTTPError(400, fmt.Sprintf("failed to load record: %s", err))
 	}
 
 	if nil == resp.Value {

cmd/astrolabe/service.go

···
 	"context"
 	"embed"
 	"errors"
+	"fmt"
 	"io/fs"
 	"net/http"
 	"os"
···
 
 func (srv *Server) errorHandler(err error, c echo.Context) {
 	code := http.StatusInternalServerError
+	var errorMessage string
 	if he, ok := err.(*echo.HTTPError); ok {
 		code = he.Code
+		errorMessage = fmt.Sprintf("%s", he.Message)
 	}
 	if code >= 500 {
 		slog.Warn("astrolabe-http-internal-error", "err", err)
 	}
 	data := pongo2.Context{
-		"statusCode": code,
+		"statusCode":   code,
+		"errorMessage": errorMessage,
+	}
+	if !c.Response().Committed {
+		c.Render(code, "error.html", data)
 	}
-	c.Render(code, "error.html", data)
 }
 
 func (srv *Server) ServeHTTP(rw http.ResponseWriter, req *http.Request) {

cmd/astrolabe/templates/error.html

···
 <center>
   <h1 style="font-size: 8em;">{{ statusCode }}</h1>
   <h2 style="font-size: 3em;">Error!</h2>
+  {% if errorMessage %}
+  <p><code>{{ errorMessage }}</code></p>
+  {% endif %}
 </center>
 {% endblock %}