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

.prettierrc

@@ -0,0 +1,6 @@
+{
+  "singleQuote": true,
+  "trailingComma": "all",
+  "printWidth": 100,
+  "tabWidth": 2
+}