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

package.json

@@ -0,0 +1,9 @@
+{
+  "name": "openclaw-oauth-sync",
+  "version": "1.0.0",
+  "private": true,
+  "description": "OpenClaw OAuth Token Sync",
+  "devDependencies": {
+    "prettier": "^3.2.0"
+  }
+}