policies: add standard policy files, formatting, and secret scanning

- Add .editorconfig, .prettierrc, .prettierignore, .gitignore
- Add Makefile with fmt, fmt-check, secret-scan, test (skip) targets
- Add package.json with prettier
- Add tools/secret-scan.sh
- Add .secret-scan-allowlist for documentation token format references
- Sanitize documentation to use generic placeholders
- Auto-format with prettier
- make check passes clean

.editorconfig

@@ -0,0 +1,12 @@
+root = true
+
+[*]
+indent_style = space
+indent_size = 2
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+[*.sh]
+indent_size = 4