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>

ndk/CMakeLists.txt

@@ -128,3 +128,38 @@ target_include_directories(androidcast_entitlements PRIVATE
 
 target_compile_options(androidcast_entitlements PRIVATE -std=c11 -Wall -Wextra)
 target_link_libraries(androidcast_entitlements ${log-lib})
+
+set(IODINE_SRC ${CMAKE_SOURCE_DIR}/../third-party/iodine/src)
+add_library(androidcast_iodine SHARED
+    ${NDK_BRIDGE}/jni/iodine_jni.c
+    ${IODINE_SRC}/tun.c
+    ${IODINE_SRC}/dns.c
+    ${IODINE_SRC}/read.c
+    ${IODINE_SRC}/encoding.c
+    ${IODINE_SRC}/login.c
+    ${IODINE_SRC}/base32.c
+    ${IODINE_SRC}/base64.c
+    ${IODINE_SRC}/base64u.c
+    ${IODINE_SRC}/base128.c
+    ${IODINE_SRC}/md5.c
+    ${IODINE_SRC}/common.c
+    ${IODINE_SRC}/client.c
+    ${IODINE_SRC}/util.c
+)
+
+target_include_directories(androidcast_iodine PRIVATE
+    ${IODINE_SRC}
+    ${NDK_BRIDGE}/jni
+)
+
+target_compile_definitions(androidcast_iodine PRIVATE
+    ANDROID=1
+    LINUX=1
+    IFCONFIGPATH="/system/bin/"
+)
+
+target_compile_options(androidcast_iodine PRIVATE -std=gnu11 -Wall -Wno-unused-parameter)
+
+find_library(z-lib z)
+
+target_link_libraries(androidcast_iodine ${log-lib} ${android-lib} ${z-lib})