Merge branch 'codex/bind-noise-peer-identities' into codex/advertise-private-media-capability

# Conflicts:
#	app/src/main/java/com/bitchat/android/mesh/BluetoothMeshService.kt
#	app/src/main/java/com/bitchat/android/mesh/MeshCore.kt
#	app/src/main/java/com/bitchat/android/mesh/MessageHandler.kt
#	app/src/main/java/com/bitchat/android/model/RoutedPacket.kt
#	app/src/test/kotlin/com/bitchat/android/mesh/MessageHandlerTest.kt

app/src/main/java/com/bitchat/android/mesh/MessageHandler.kt

@@ -3,7 +3,6 @@ package com.bitchat.android.mesh
 import android.util.Log
 import com.bitchat.android.model.BitchatMessage
 import com.bitchat.android.model.BitchatMessageType
-import com.bitchat.android.model.IdentityAnnouncement
 import com.bitchat.android.model.RoutedPacket
 import com.bitchat.android.protocol.BitchatPacket
 import com.bitchat.android.protocol.MessageType
@@ -13,6 +12,11 @@ import kotlinx.coroutines.*
 import java.util.*
 import kotlin.random.Random
 
+sealed class AnnounceHandlingResult {
+    data class Accepted(val isFirst: Boolean) : AnnounceHandlingResult()
+    object Rejected : AnnounceHandlingResult()
+}
+
 /**
  * Handles processing of different message types
  * Extracted from BluetoothMeshService for better separation of concerns
@@ -216,10 +220,14 @@ class MessageHandler(private val myPeerID: String, private val appContext: andro
      * Handle announce message with TLV decoding and signature verification - exactly like iOS
      */
     suspend fun handleAnnounce(routed: RoutedPacket): Boolean {
+        return (handleAnnounceWithResult(routed) as? AnnounceHandlingResult.Accepted)?.isFirst ?: false
+    }
+
+    suspend fun handleAnnounceWithResult(routed: RoutedPacket): AnnounceHandlingResult {
         val packet = routed.packet
         val peerID = routed.peerID ?: "unknown"
 
-        if (peerID == myPeerID) return false
+        if (peerID == myPeerID) return AnnounceHandlingResult.Rejected
 
         // Peers use wall-clock packet timestamps; tolerate moderate device clock skew
         // during identity learning, or later signed messages cannot be verified.
@@ -227,28 +235,21 @@ class MessageHandler(private val myPeerID: String, private val appContext: andro
         val clockSkewMs = kotlin.math.abs(now - packet.timestamp.toLong())
         if (clockSkewMs > ANNOUNCE_CLOCK_SKEW_TOLERANCE_MS) {
             Log.w(TAG, "Ignoring ANNOUNCE from ${peerID.take(8)} with excessive clock skew (${clockSkewMs}ms > ${ANNOUNCE_CLOCK_SKEW_TOLERANCE_MS}ms)")
-            return false
+            return AnnounceHandlingResult.Rejected
         } else if (clockSkewMs > com.bitchat.android.util.AppConstants.Mesh.STALE_PEER_TIMEOUT_MS) {
             Log.w(TAG, "Accepting ANNOUNCE from ${peerID.take(8)} within clock skew tolerance (${clockSkewMs}ms)")
         }
         
-        // Try to decode as iOS-compatible IdentityAnnouncement with TLV format
-        val announcement = IdentityAnnouncement.decode(packet.payload)
+        val announcement = AnnouncementIdentityValidator.verify(packet, peerID) { signature, data, key ->
+            delegate?.verifyEd25519Signature(signature, data, key) ?: false
+        }
         if (announcement == null) {
-            Log.w(TAG, "Failed to decode announce from $peerID as iOS-compatible TLV format")
-            return false
-        }
-        
-        // Verify packet signature using the announced signing public key
-        var verified = false
-        if (packet.signature != null) {
-            // Verify that the packet was signed by the signing private key corresponding to the announced signing public key
-            verified = delegate?.verifyEd25519Signature(packet.signature!!, packet.toBinaryDataForSigning()!!, announcement.signingPublicKey) ?: false
-            if (!verified) {
-                Log.w(TAG, "⚠️ Signature verification for announce failed ${peerID.take(8)}")
-            }
+            Log.w(TAG, "Rejecting malformed, unbound, or invalidly signed ANNOUNCE from ${peerID.take(8)}")
+            return AnnounceHandlingResult.Rejected
         }
 
+        var verified = true
+
         // Check for existing peer with different noise public key
         // If existing peer has a different noise public key, do not consider this verified
         val existingPeer = delegate?.getPeerInfo(peerID)
@@ -258,10 +259,21 @@ class MessageHandler(private val myPeerID: String, private val appContext: andro
             verified = false
         }
 
+        if (
+            existingPeer?.signingPublicKey != null &&
+            !existingPeer.signingPublicKey!!.contentEquals(announcement.signingPublicKey)
+        ) {
+            Log.w(
+                TAG,
+                "Rejecting signing-key replacement for ${peerID.take(8)} without authenticated peer-state proof"
+            )
+            verified = false
+        }
+
         // Require verified announce; ignore otherwise (no backward compatibility)
         if (!verified) {
             Log.w(TAG, "❌ Ignoring unverified announce from ${peerID.take(8)}...")
-            return false
+            return AnnounceHandlingResult.Rejected
         }
         
         // Successfully decoded TLV format exactly like iOS
@@ -284,19 +296,6 @@ class MessageHandler(private val myPeerID: String, private val appContext: andro
             capabilities = announcement.capabilities
         ) ?: false
 
-        // Promotion of security-sensitive capabilities happens only after the
-        // signature check above and must additionally bind to the authenticated
-        // Noise remote-static key in the transport service.
-        delegate?.onVerifiedAnnouncementProcessed(peerID)
-
-        // Update peer ID binding with noise public key for identity management
-        delegate?.updatePeerIDBinding(
-            newPeerID = peerID,
-            nickname = nickname,
-            publicKey = noisePublicKey,
-            previousPeerID = null
-        )
-        
         // Update mesh graph from gossip neighbors (only if TLV present)
         try {
             val neighborsOrNull = com.bitchat.android.services.meshgraph.GossipTLV.decodeNeighborsFromAnnouncementPayload(packet.payload)
@@ -305,7 +304,7 @@ class MessageHandler(private val myPeerID: String, private val appContext: andro
         } catch (_: Exception) { }
 
         Log.d(TAG, "✅ Processed verified TLV announce: stored identity for $peerID")
-        return isFirstAnnounce
+        return AnnounceHandlingResult.Accepted(isFirstAnnounce)
     }
     
     /**
@@ -647,8 +646,6 @@ interface MessageHandlerDelegate {
     fun hasNoiseSession(peerID: String): Boolean
     fun initiateNoiseHandshake(peerID: String)
     fun processNoiseHandshakeMessage(payload: ByteArray, peerID: String): ByteArray?
-    fun updatePeerIDBinding(newPeerID: String, nickname: String,
-                           publicKey: ByteArray, previousPeerID: String?)
     
     // Message operations
     fun decryptChannelMessage(encryptedContent: ByteArray, channel: String): String?