[Auth] Choose which auth storage to use based on config (#5792)

This PR is a follow-up to #5591. It allows users to choose which auth
storage mode they want by using the new
`cli_auth_credentials_store_mode` config.

codex-rs/core/Cargo.toml

@@ -39,7 +39,12 @@ eventsource-stream = { workspace = true }
 futures = { workspace = true }
 http = { workspace = true }
 indexmap = { workspace = true }
-keyring = { workspace = true }
+keyring = { workspace = true, features = [
+    "apple-native",
+    "crypto-rust",
+    "linux-native-async-persistent",
+    "windows-native",
+] }
 libc = { workspace = true }
 mcp-types = { workspace = true }
 os_info = { workspace = true }