fix: guard macos-ne feature with target_os = "macos" in cfg expressions (#1962)

All 13 occurrences of `any(target_os = "ios", feature = "macos-ne")` are
replaced with `any(target_os = "ios", all(target_os = "macos", feature = "macos-ne"))`.

Previously, enabling `macos-ne` on non-macOS platforms (e.g. `--all-features`
on Linux) would incorrectly compile macOS/mobile-specific code paths, causing
build failures or wrong runtime behavior.

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

easytier/src/gateway/tcp_proxy.rs

@@ -539,7 +539,10 @@ impl<C: NatDstConnector> TcpProxy<C> {
             || self.global_ctx.no_tun()
             || cfg!(any(
                 target_os = "android",
-                any(target_os = "ios", feature = "macos-ne"),
+                any(
+                    target_os = "ios",
+                    all(target_os = "macos", feature = "macos-ne")
+                ),
                 target_env = "ohos"
             ))
         {