Auto-commit extra files (#197)

Whenever Dyad does a commit from a proposal, it will automatically amend
the commit with outside changes (e.g. made outside of Dyad).

This helps avoid a lot of user confusion, e.g.
https://github.com/dyad-sh/dyad/issues/187

https://www.reddit.com/r/dyadbuilders/comments/1kjysc0/error_pushing_images/

Edge cases:
If a user adds a file outside of Dyad, and then they hit retry, it will
revert these outside changes, but it's still technically in the version
history, so I think it's OK. This should also be a pretty unusual
situation.

Fixes #164 
Fixes #187

src/lib/toast.ts

@@ -58,11 +58,23 @@ export const showLoading = <T>(
   });
 };
 
-export const showUncommittedFilesWarning = (files: string[]) => {
-  showWarning(
-    `Some changed files were not committed. Please use git to manually commit them.
+export const showExtraFilesToast = ({
+  files,
+  error,
+}: {
+  files: string[];
+  error?: string;
+}) => {
+  if (error) {
+    showError(
+      `Error committing files ${files.join(", ")} changed outside of Dyad: ${error}`,
+    );
+  } else {
+    showWarning(
+      `Files changed outside of Dyad have automatically been committed:
     \n\n${files.join("\n")}`,
-  );
+    );
+  }
 };
 
 // Re-export for direct use