Build 53: Windows + Android support with a per-platform Nym sidecar

Ship the bundled nym-socks5-client on Windows and Android, not just Linux:
- sidecar.rs resolves the binary per platform — nym-socks5-client.exe on
  Windows; on Android the sidecar rides in the APK jniLibs as
  libnym_socks5_client.so and is launched from the native-library dir (the
  one exec-allowed path), located via NATIVE_LIBS_DIR.
- Restore a vendored, statically-linked OpenSSL. Upstream Grim got this from
  arti's static feature; dropping arti for Nym took it with it, which broke
  Android/cross builds (no system OpenSSL for the target) and left desktop
  dynamically linked to libssl. Inert on Windows/macOS (SChannel/Security.fw).
- android.sh bundles the sidecar into jniLibs per ABI; scripts/nym-android.sh
  cross-builds it. Onboarding copy: Tor -> the Nym mixnet.

Verified end to end on an x86_64 emulator: the sidecar extracts, launches,
initialises, and opens the mixnet SOCKS5 proxy on 127.0.0.1:1080.

src/gui/views/goblin/onboarding.rs

@@ -194,8 +194,8 @@ impl OnboardingContent {
 			(
 				"Send like a message",
 				"Pay a @username or npub and it arrives as an end-to-end \
-				 encrypted message over nostr and Tor — no one in between can \
-				 see the amount or who's involved.",
+				 encrypted message over nostr and the Nym mixnet — no one in \
+				 between can see the amount or who's involved.",
 			),
 			(
 				"Yours alone",