Implement native iodine client and fix RA heartbeat URL resolution.

Bundle iodine 0.7.0 with JNI TUN bridge; apply BE iodine credentials on connect; canonical heartbeat URL fallback.

Co-authored-by: Cursor <cursoragent@cursor.com>

third-party/iodine/README-android.txt

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+
+
+iodine - https://code.kryo.se/iodine
+
+***********************************
+
+Extra README file for Android
+
+
+== Running iodine on Android:
+1. Get root access on your android device
+
+2. Find/build a compatible tun.ko for your specific Android kernel
+
+3. Copy tun.ko and the iodine binary to your device:
+   (Almost all devices need the armeabi binary. Only Intel powered
+   ones need the x86 build.)
+
+		adb push tun.ko /data/local/tmp
+		adb push iodine /data/local/tmp
+		adb shell
+		su
+		cd /data/local/tmp
+		chmod 777 iodine
+
+4. Run iodine (see the man page for parameters)
+
+		./iodine ...
+
+For more information: http://blog.bokhorst.biz/5123
+
+== Building iodine for Android:
+1. Download and install the Android SDK and NDK
+
+2. Download and unpack the iodine sources
+
+3. Build:
+	cd src
+	make base64u.h base64u.c
+	ndk-build NDK_PROJECT_PATH=. APP_BUILD_SCRIPT=Android.16.mk APP_PLATFORM=android-16
+
+   or run "make cross-android" in the iodine root directory.
+   To build for other archs, specify TARGET_ARCH_ABI:
+		"make cross-android TARGET_ARCH_ABI=x86"
+
+   For older android versions (pre-kitkat), build with "make cross-android-old" in the
+   root directory, or manually like above but with APP_PLATFORM=android-3 and with
+   APP_BUILD_SCRIPT=Android.mk
+
+   The iodine binary ends up in src/libs/<arch>/iodine