Initial commit: gtea CLI tool

Go CLI that wraps the Gitea API and git to create repos, commit,
push, and pull without leaving the terminal.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

main.go

@@ -0,0 +1,7 @@
+package main
+
+import "gtea/cmd"
+
+func main() {
+	cmd.Execute()
+}