feat(mini): add compact native EasyTier client (#2479)

Add a native EasyTier proof-of-concept binary with TCP and UDP
transports, TUN, UDP hole punching, AES-GCM, and a read-only RPC
portal.

Introduce a release-derived mini profile and musl linker policy so
x86_64, big-endian MIPS, and little-endian MIPS stay below the strict
5,000,000-byte target without UPX.

Cargo.toml

@@ -6,6 +6,7 @@ members = [
     "easytier",
     "easytier-gui/src-tauri",
     "easytier-web",
+    "easytier-contrib/easytier-mini",
     "easytier-contrib/easytier-ffi",
     "easytier-contrib/easytier-uptime",
     "easytier-contrib/easytier-android-jni",
@@ -29,3 +30,8 @@ lto = true
 codegen-units = 1
 opt-level = 3
 strip = true
+
+[profile.mini]
+inherits = "release"
+opt-level = "z"
+strip = "symbols"