fix(start): enable Send Feedback / Release Notes on the start tab

The start (welcome) tab blocks any command that isn't NEW/OPEN/EXIT/QUIT,
so the Contribute and Release Notes buttons did nothing but print
"No drawing open". REPORT and CHANGELOG (and ABOUT) only open a URL or a
dialog and need no drawing, so allow them through.

Also rename the "Contribute" button to "Send Feedback" (#44) and update
the REPORT status line to match.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/view.rs

@@ -3730,7 +3730,7 @@ pub(super) fn start_page_view<'a>() -> Element<'a, Message> {
 
     let secondary_row = row![
         outline_btn(
-            "Contribute",
+            "Send Feedback",
             Message::RibbonToolClick {
                 tool_id: "REPORT".to_string(),
                 event: crate::modules::ModuleEvent::Command("REPORT".to_string()),