Add macOS native credential sync to supported feature flags

.env.template

@@ -411,6 +411,7 @@
 ## - "biometrics-sdk-ipc": Enable biometric unlock over the SDK IPC framework (Desktop >= 2026.9.0, Browser >= 2026.9.0)
 ## - "windows-native-credential-sync": Register the desktop app as a passkey provider in Windows, so passkeys in the vault can be used by other apps and browsers.
 ##   Requires the Microsoft Store (appx) build of the desktop app. Stable releases up to and including 2026.9.1 lack the required plugin registration, so it has no effect there yet.
+## - "macos-native-credential-sync": Enable the desktop app as a passkey provider on macOS, so passkeys in the vault can be used by other apps and browsers.
 # EXPERIMENTAL_CLIENT_FEATURE_FLAGS=
 
 ## Require new device emails. When a user logs in an email is required to be sent.

src/config.rs

@@ -1516,6 +1516,7 @@ pub const SUPPORTED_FEATURE_FLAGS: &[&str] = &[
     // Key Management Team
     "biometrics-sdk-ipc",
     "windows-native-credential-sync",
+    "macos-native-credential-sync",
     // Mobile Team
     "pm-34171-card-scanner",
     // Platform Team