Say never subscribed only when the peer never subscribed

Both handlers read the live CCCD flag at disconnect, so a peer that subscribed
and then unsubscribed - what a BlueZ central does on every teardown - was
reported as one that never subscribed at all.

src/platform/esp32/ESP32BLEGattMesh.cpp

@@ -32,7 +32,8 @@ struct Link {
     bool used;
     uint16_t conn;
     uint16_t chunk;
-    bool subscribed; // wrote the CCCD: a notify target
+    bool subscribed;     // wrote the CCCD: a notify target
+    bool everSubscribed; // subscribed at any point, which outlives an unsubscribe
     // Arrived through the mesh-peer advertisement (instance 2). Set in onGapEvent CONNECT and nowhere
     // else: it is the slot accounting for that advertisement and the "not the phone's session" signal
     // NimbleBluetooth's onDisconnect keys off, so it must mean exactly "came in on instance 2". It used
@@ -94,6 +95,7 @@ Link *addLink(uint16_t conn, bool viaMeshAdv)
         l.conn = conn;
         l.chunk = chunkFor(conn);
         l.subscribed = false;
+        l.everSubscribed = false;
         l.viaMeshAdv = viaMeshAdv;
         return &l;
     }
@@ -191,6 +193,7 @@ class MeshPeerCallbacks : public BLECharacteristicCallbacks
             std::lock_guard<std::mutex> guard(lock);
             if (Link *l = addLink(desc->conn_handle, false)) {
                 l->subscribed = subscribed;
+                l->everSubscribed |= subscribed;
                 l->chunk = chunkFor(desc->conn_handle);
                 viaMeshAdv = l->viaMeshAdv;
             }
@@ -361,7 +364,7 @@ bool ESP32BLEGattMesh::onDisconnect(uint16_t connHandle)
         std::lock_guard<std::mutex> guard(lock);
         if (Link *l = findLink(connHandle)) {
             viaMeshAdv = l->viaMeshAdv;
-            subscribed = l->subscribed;
+            subscribed = l->everSubscribed;
             l->used = false;
             pushRx(connHandle, nullptr, 0); // the pump drops its half-built packets
         }

src/platform/nrf52/NRF52BLEGattMesh.cpp

@@ -18,7 +18,8 @@ concurrency::Lock lock;
 struct Link {
     bool used;
     uint16_t conn;
-    bool subscribed; // wrote the CCCD: a notify target, and the mark of a mesh peer
+    bool subscribed;     // wrote the CCCD: a notify target, and the mark of a mesh peer
+    bool everSubscribed; // subscribed at any point, which outlives an unsubscribe
 };
 std::array<Link, 4> links{};
 
@@ -68,6 +69,7 @@ Link *addLink(uint16_t conn)
         l.used = true;
         l.conn = conn;
         l.subscribed = false;
+        l.everSubscribed = false;
         return &l;
     }
     return nullptr;
@@ -117,6 +119,7 @@ void onCccd(uint16_t conn, BLECharacteristic *, uint16_t value)
         concurrency::LockGuard guard(&lock);
         if (Link *l = addLink(conn))
             l->subscribed = subscribed;
+        l->everSubscribed |= subscribed;
     }
     LOG_INFO("BLE GATT mesh: conn %u %s (chunk %u)", conn, subscribed ? "subscribed" : "unsubscribed", chunkFor(conn));
     if (bleGattMeshHandler)
@@ -183,7 +186,7 @@ bool NRF52BLEGattMesh::onDisconnect(uint16_t conn)
     {
         concurrency::LockGuard guard(&lock);
         if (Link *l = findLink(conn)) {
-            subscribed = l->subscribed;
+            subscribed = l->everSubscribed;
             l->used = false;
             pushRx(conn, nullptr, 0); // the pump drops its half-built packets
         }