feat: add user-defined safe commands configuration and approval logic #380 (#386)

This pull request adds a feature that allows users to configure
auto-approved commands via a `safeCommands` array in the configuration
file.

## Related Issue
#380 

## Changes
- Added loading and validation of the `safeCommands` array in
`src/utils/config.ts`
- Implemented auto-approval logic for commands matching `safeCommands`
prefixes in `src/approvals.ts`
- Added test cases in `src/tests/approvals.test.ts` to verify
`safeCommands` behavior
- Updated documentation with examples and explanations of the
configuration

codex-cli/src/approvals.ts

@@ -4,6 +4,7 @@ import {
   identify_files_added,
   identify_files_needed,
 } from "./utils/agent/apply-patch";
+import { loadConfig } from "./utils/config";
 import * as path from "path";
 import { parse } from "shell-quote";
 
@@ -296,6 +297,24 @@ export function isSafeCommand(
 ): SafeCommandReason | null {
   const [cmd0, cmd1, cmd2, cmd3] = command;
 
+  const config = loadConfig();
+  if (config.safeCommands && Array.isArray(config.safeCommands)) {
+    for (const safe of config.safeCommands) {
+      // safe: "npm test" → ["npm", "test"]
+      const safeArr = typeof safe === "string" ? safe.trim().split(/\s+/) : [];
+      if (
+        safeArr.length > 0 &&
+        safeArr.length <= command.length &&
+        safeArr.every((v, i) => v === command[i])
+      ) {
+        return {
+          reason: "User-defined safe command",
+          group: "User config",
+        };
+      }
+    }
+  }
+
   switch (cmd0) {
     case "cd":
       return {