Feature/fragmentation fixes (#453)

* Fix fragmentation + BLE long-write + padding

- Accumulate CBATTRequest long writes by offset and decode once per central
- Decode original packet after fragment reassembly (preserve flags/compression)
- Switch MessagePadding to strict PKCS#7 and validate before unpadding
- Make BinaryProtocol.decode robust: try raw first, then unpad fallback
- Unpad frames before BLE notify; fragment when exceeding centrals' max update length
- Skip notify path when max update length < 21 bytes (protocol minimum)

Verified large PMs and announces route without decode errors and peers show reliably.

* Tests: fix weak delegate lifetime, legacy constants, and unused vars; fragment unpadded frames

- BLEServiceTests: hold strong reference to MockBitchatDelegate
- IntegrationTests: fix inline comment braces; replace removed types with test-safe values; use numeric 0x06 for legacy handshake resp checks
- BinaryProtocolTests: remove unused minResult variable
- BLEService: fragment the unpadded frame so fragments are efficient

* tests: add Noise rehandshake recovery test; document in-memory test bus and autoFlood; stabilize large-network broadcast

* tests: align suite with current behavior (compression, padding, routing, nonce); deflake and stabilize

---------

Co-authored-by: jack <jackjackbits@users.noreply.github.com>

bitchatTests/BLEServiceTests.swift

@@ -66,12 +66,13 @@ final class BLEServiceTests: XCTestCase {
     func testSendPublicMessage() {
         let expectation = XCTestExpectation(description: "Message sent")
         
-        service.delegate = MockBitchatDelegate { message in
+        let delegate = MockBitchatDelegate { message in
             XCTAssertEqual(message.content, "Hello, world!")
             XCTAssertEqual(message.sender, "TestUser")
             XCTAssertFalse(message.isPrivate)
             expectation.fulfill()
         }
+        service.delegate = delegate
         
         service.sendMessage("Hello, world!")
         
@@ -82,13 +83,14 @@ final class BLEServiceTests: XCTestCase {
     func testSendPrivateMessage() {
         let expectation = XCTestExpectation(description: "Private message sent")
         
-        service.delegate = MockBitchatDelegate { message in
+        let delegate = MockBitchatDelegate { message in
             XCTAssertEqual(message.content, "Secret message")
             XCTAssertEqual(message.sender, "TestUser")
             XCTAssertTrue(message.isPrivate)
             XCTAssertEqual(message.recipientNickname, "Bob")
             expectation.fulfill()
         }
+        service.delegate = delegate
         
         service.sendPrivateMessage("Secret message", to: "PEER5678", recipientNickname: "Bob", messageID: "MSG123")
         
@@ -99,11 +101,12 @@ final class BLEServiceTests: XCTestCase {
     func testSendMessageWithMentions() {
         let expectation = XCTestExpectation(description: "Message with mentions sent")
         
-        service.delegate = MockBitchatDelegate { message in
+        let delegate = MockBitchatDelegate { message in
             XCTAssertEqual(message.content, "@alice @bob check this out")
             XCTAssertEqual(message.mentions, ["alice", "bob"])
             expectation.fulfill()
         }
+        service.delegate = delegate
         
         service.sendMessage("@alice @bob check this out", mentions: ["alice", "bob"])
         
@@ -115,11 +118,12 @@ final class BLEServiceTests: XCTestCase {
     func testSimulateIncomingMessage() {
         let expectation = XCTestExpectation(description: "Message received")
         
-        service.delegate = MockBitchatDelegate { message in
+        let delegate = MockBitchatDelegate { message in
             XCTAssertEqual(message.content, "Incoming message")
             XCTAssertEqual(message.sender, "RemoteUser")
             expectation.fulfill()
         }
+        service.delegate = delegate
         
         let incomingMessage = BitchatMessage(
             id: "MSG456",
@@ -142,10 +146,11 @@ final class BLEServiceTests: XCTestCase {
     func testSimulateIncomingPacket() {
         let expectation = XCTestExpectation(description: "Packet processed")
         
-        service.delegate = MockBitchatDelegate { message in
+        let delegate = MockBitchatDelegate { message in
             XCTAssertEqual(message.content, "Packet message")
             expectation.fulfill()
         }
+        service.delegate = delegate
         
         let message = BitchatMessage(
             id: "MSG789",
@@ -209,9 +214,11 @@ final class BLEServiceTests: XCTestCase {
     func testMessageDeliveryHandler() {
         let expectation = XCTestExpectation(description: "Delivery handler called")
         
-        service.messageDeliveryHandler = { message in
-            XCTAssertEqual(message.content, "Test delivery")
-            expectation.fulfill()
+        service.packetDeliveryHandler = { packet in
+            if let msg = BitchatMessage.fromBinaryPayload(packet.payload) {
+                XCTAssertEqual(msg.content, "Test delivery")
+                expectation.fulfill()
+            }
         }
         
         service.sendMessage("Test delivery")