Build 66: disable clearnet update-check; drop sidecar build steps

Security (audit H-2): the legacy update check is OFF by default. It hit
code.gri.mw (GRIM's gitea) directly over CLEARNET via the old HttpClient —
leaking "this user runs Goblin" metadata on every wallet-list view, which
defeats the nothing-clearnet mixnet model, and it pointed at the wrong
project's releases anyway. Opt-in only until reworked to run over the
mixnet against Goblin's own releases.

Build: with the Nym SDK linked in-process there's no sidecar binary to
embed or bundle. linux/build_release.sh drops the GOBLIN_NYM_UNIX_BIN
embed (AppImage is one self-contained binary); scripts/android.sh stops
bundling nym-socks5-client into jniLibs (the cdylib links nym-sdk
directly); scripts/nym-android.sh deleted.

scripts/android.sh

@@ -49,21 +49,8 @@ function build_lib() {
   sed -i -e 's/"cdylib","rlib"]/"rlib"]/g' Cargo.toml
   rm -f Cargo.toml-e
 
-  # Bundle the Nym SOCKS5 sidecar beside libgrim.so. Named lib*.so so Android
-  # ships it in the APK's jniLibs and extracts it to the native-library dir —
-  # the only exec-allowed location for a child process (manifest needs
-  # extractNativeLibs=true). Built from the Nym workspace; see scripts/nym-android.sh.
-  [[ $1 == "v7" ]] && nym_target=armv7-linux-androideabi
-  [[ $1 == "v8" ]] && nym_target=aarch64-linux-android
-  [[ $1 == "x86" ]] && nym_target=x86_64-linux-android
-  nym_bin="${NYM_DIR:-../nym/target}/${nym_target}/release/nym-socks5-client"
-  if [ -f "${nym_bin}" ]; then
-    cp "${nym_bin}" "android/app/src/main/jniLibs/${arch}/libnym_socks5_client.so"
-    echo "bundled Nym sidecar: jniLibs/${arch}/libnym_socks5_client.so"
-  else
-    echo "WARN: Nym sidecar missing at ${nym_bin} — APK will have NO mixnet sidecar"
-    success=0
-  fi
+  # The Nym mixnet is linked INTO libgrim.so (nym-sdk is a regular dependency),
+  # so there is no separate sidecar binary to cross-build or bundle into jniLibs.
 }
 
 ### Build application