Add security and git policies, make repo a model example

- Never commit secrets; comprehensive .gitignore with fetch URL
- Never force-push to main
- go mod tidy before committing
- make hooks target with Go repo detection
- Add .editorconfig, .prettierrc, .prettierignore
- Template files URL for new repo setup

.editorconfig

@@ -0,0 +1,12 @@
+root = true
+
+[*]
+indent_style = space
+indent_size = 4
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+[Makefile]
+indent_style = tab