fix: show real identity fingerprint (SHA-256 full format) on Android home screen

android/app/src/main/java/com/wzp/engine/WzpEngine.kt

@@ -159,6 +159,18 @@ class WzpEngine(private val callback: WzpCallback) {
     private external fun nativeWriteAudioDirect(handle: Long, buffer: java.nio.ByteBuffer, sampleCount: Int): Int
     private external fun nativeReadAudioDirect(handle: Long, buffer: java.nio.ByteBuffer, maxSamples: Int): Int
     private external fun nativeDestroy(handle: Long)
+
+    companion object {
+        init { System.loadLibrary("wzp_android") }
+
+        /** Get the identity fingerprint for a seed hex. No engine needed. */
+        @JvmStatic
+        private external fun nativeGetFingerprint(seedHex: String): String?
+
+        /** Compute the full identity fingerprint (xxxx:xxxx:...) from a seed hex string. */
+        @JvmStatic
+        fun getFingerprint(seedHex: String): String = nativeGetFingerprint(seedHex) ?: ""
+    }
     private external fun nativePingRelay(handle: Long, relay: String): String?
     private external fun nativeStartSignaling(handle: Long, relay: String, seed: String, token: String, alias: String): Int
     private external fun nativePlaceCall(handle: Long, targetFp: String): Int
@@ -208,11 +220,6 @@ class WzpEngine(private val callback: WzpCallback) {
         return nativeAnswerCall(nativeHandle, callId, mode)
     }
 
-    companion object {
-        init {
-            System.loadLibrary("wzp_android")
-        }
-    }
 }
 
 /** Integer constants matching the Rust [CallState] enum ordinals. */

android/app/src/main/java/com/wzp/ui/call/InCallScreen.kt

@@ -431,14 +431,16 @@ fun InCallScreen(
 
                 Spacer(modifier = Modifier.height(20.dp))
 
-                // Identity
-                val fp = if (seedHex.length >= 16) seedHex.take(16) else ""
+                // Identity — compute real fingerprint from seed
+                val fullFp = remember(seedHex) {
+                    if (seedHex.length >= 64) com.wzp.engine.WzpEngine.getFingerprint(seedHex) else ""
+                }
                 Row(verticalAlignment = Alignment.CenterVertically) {
-                    if (fp.isNotEmpty()) {
-                        Identicon(fingerprint = seedHex, size = 28.dp)
+                    if (fullFp.isNotEmpty()) {
+                        Identicon(fingerprint = fullFp, size = 28.dp)
                         Spacer(modifier = Modifier.width(8.dp))
                         CopyableFingerprint(
-                            fingerprint = fp.chunked(4).joinToString(":"),
+                            fingerprint = fullFp,
                             style = MaterialTheme.typography.bodySmall.copy(fontFamily = FontFamily.Monospace),
                             color = TextDim
                         )