Feat/0-cost hops for favorite routers (#7992)

* feat: implement router hop preservation for router-to-router communication

- Preserve hop_limit when both local device and previous relay are routers/CLIENT_BASE
- Only preserve hops for favorite routers to prevent abuse
- Apply to both FloodingRouter and NextHopRouter
- Update hop counting logic in MeshService for router-to-router communication

This allows routers to communicate over longer distances without
consuming hop limits, improving mesh network efficiency for
infrastructure nodes.

* chore: update protobufs submodule to latest

* Optimized to check friend list first before nodedb.

* Reverting unintended changes

* revert: remove protobufs submodule update

This reverts the protobufs submodule back to a84657c22 to remove
unintended changes from this branch.

* Slight rewrite to remove flawed NO_RELAY_NODE logic and added logic to add isFirstHop. If isFirstHop, always decrease hop_limit to avoid retry logic.

* DRY code. Remove NodeInfo logic that was left over.

* Trunk formatting

src/mesh/Router.cpp

@@ -69,6 +69,58 @@ Router::Router() : concurrency::OSThread("Router"), fromRadioQueue(MAX_RX_FROMRA
     cryptLock = new concurrency::Lock();
 }
 
+bool Router::shouldDecrementHopLimit(const meshtastic_MeshPacket *p)
+{
+    // First hop MUST always decrement to prevent retry issues
+    bool isFirstHop = (p->hop_start != 0 && p->hop_start == p->hop_limit);
+    if (isFirstHop) {
+        return true; // Always decrement on first hop
+    }
+
+    // Check if both local device and previous relay are routers (including CLIENT_BASE)
+    bool localIsRouter =
+        IS_ONE_OF(config.device.role, meshtastic_Config_DeviceConfig_Role_ROUTER, meshtastic_Config_DeviceConfig_Role_ROUTER_LATE,
+                  meshtastic_Config_DeviceConfig_Role_CLIENT_BASE);
+
+    // If local device isn't a router, always decrement
+    if (!localIsRouter) {
+        return true;
+    }
+
+    // For subsequent hops, check if previous relay is a favorite router
+    // Optimized search for favorite routers with matching last byte
+    // Check ordering optimized for IoT devices (cheapest checks first)
+    for (int i = 0; i < nodeDB->getNumMeshNodes(); i++) {
+        meshtastic_NodeInfoLite *node = nodeDB->getMeshNodeByIndex(i);
+        if (!node)
+            continue;
+
+        // Check 1: is_favorite (cheapest - single bool)
+        if (!node->is_favorite)
+            continue;
+
+        // Check 2: has_user (cheap - single bool)
+        if (!node->has_user)
+            continue;
+
+        // Check 3: role check (moderate cost - multiple comparisons)
+        if (!IS_ONE_OF(node->user.role, meshtastic_Config_DeviceConfig_Role_ROUTER,
+                       meshtastic_Config_DeviceConfig_Role_ROUTER_LATE, meshtastic_Config_DeviceConfig_Role_CLIENT_BASE)) {
+            continue;
+        }
+
+        // Check 4: last byte extraction and comparison (most expensive)
+        if (nodeDB->getLastByteOfNodeNum(node->num) == p->relay_node) {
+            // Found a favorite router match
+            LOG_DEBUG("Identified favorite relay router 0x%x from last byte 0x%x", node->num, p->relay_node);
+            return false; // Don't decrement hop_limit
+        }
+    }
+
+    // No favorite router match found, decrement hop_limit
+    return true;
+}
+
 /**
  * do idle processing
  * Mostly looking in our incoming rxPacket queue and calling handleReceived.