Name the button that gets past a signature mismatch

The advice was "rebuild this app on this machine", which somebody can
follow and still be stuck: nothing about a changed keystore moves the
checkout, so the component is not stale and neither a pull nor Update
runs the build. Rebuild is the one control that builds regardless, so
the message says so.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

server/src/strip.rs

@@ -145,10 +145,17 @@ fn strip_debug_symbols(src_path: &Path) -> Result<PathBuf> {
         let _ = std::fs::remove_file(&slim_path);
         let _ = std::fs::remove_file(with_suffix(&slim_path, ".idsig"));
         anyhow::bail!(
+            // Rebuild is named rather than left as "rebuild it": the
+            // checkout has not moved, so nothing about this makes the
+            // component stale and neither a pull nor Update will run the
+            // build. Rebuild is the one control that builds anyway, and
+            // without saying so the advice is one somebody can follow and
+            // still be stuck.
             "{} is signed by {}, but the debug keystore at {} signs as {} -- a stripped copy \
              signed with it is a different app to Android, and the phone would refuse it with \
-             \"App not installed\". Rebuild this app on this machine, or restore the debug \
+             \"App not installed\". Press Rebuild on this project to build it again with the \
-             keystore it was built with.",
+             key that is here now (a pull will not: nothing in the checkout changed), or \
+             restore the debug keystore it was built with.",
             src_path.display(),
             built_by.iter().cloned().collect::<Vec<_>>().join(", "),
             sdk::debug_keystore_path()?.display(),