crypto: fix signature verification for initial commit

initial commit does not have a parent commit and should be excluded from
the signature check.

Signed-off-by: oppiliappan <[e-mail]>

crypto/verify.go

···
 	payload := strings.Builder{}
 
 	fmt.Fprintf(&payload, "tree %s\n", commit.Commit.Tree)
-	fmt.Fprintf(&payload, "parent %s\n", commit.Commit.Parent)
+	if commit.Commit.Parent != "" {
+		fmt.Fprintf(&payload, "parent %s\n", commit.Commit.Parent)
+	}
 	fmt.Fprintf(&payload, "author %s\n", author.String())
 	fmt.Fprintf(&payload, "committer %s\n", committer.String())
 	if commit.Commit.ChangedId != "" {

flake.nix

···
     inherit (gitignore.lib) gitignoreSource;
   in {
     overlays.default = final: prev: let
-      goModHash = "sha256-ZckpIPqFk7/XBiEJUbmrAzdjAxV62hv896xqAXF2aZs=";
+      goModHash = "sha256-QPyeKKr7YMblwicQNemu3OamXwg7fVie6/IY10vQCl4=";
       appviewDeps = {
         inherit htmx-src lucide-src inter-fonts-src ibm-plex-mono-src goModHash gitignoreSource;
       };