feat(node-info): expose MaxMessageSize node info item (#4018)

* feat(node-info): expose MaxMessageSize node info item

Add a `MaxMessageSize` entry to `NodeInfoId` so the max message size
(in bytes) accepted by the relay protocol can be queried through the
node info surface, consumed by both the debug API and the FFI
`get_node_info` / `get_available_node_info_ids` calls.

The value is read from the mounted relay's `maxMessageSize` and is empty
when the relay protocol is not mounted on the node (e.g. light nodes),
mirroring the existing `MyMixPubKey` handling.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* refactor(node-info): source MaxMessageSize from node config

Read the reported value from `conf.maxMessageSizeBytes` instead of the
mounted relay. The relay only holds a copy of the configured value and is
absent on relay-disabled (light) nodes, which would report an empty
string. Sourcing from the config makes the item always available and
reflects the node's configured limit directly.

WakuStateInfo now holds the WakuConf it reports on; init takes it as an
argument.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

logos_delivery/waku/factory/waku_state_info.nim

@@ -7,6 +7,7 @@
 import std/[tables, sequtils, strutils]
 import metrics, eth/p2p/discoveryv5/enr, libp2p/peerid, stew/byteutils
 import logos_delivery/waku/[waku_node, net/bound_ports]
+import logos_delivery/waku/factory/waku_conf
 
 type
   NodeInfoId* {.pure.} = enum
@@ -17,9 +18,11 @@ type
     MyPeerId
     MyBoundPorts
     MyMixPubKey
+    MaxMessageSize
 
   WakuStateInfo* {.requiresInit.} = object
     node: WakuNode
+    conf: WakuConf
 
 proc getAllPossibleInfoItemIds*(self: WakuStateInfo): seq[NodeInfoId] =
   ## Returns all possible options that can be queried to learn about the node's information.
@@ -52,8 +55,11 @@ proc getNodeInfoItem*(self: WakuStateInfo, infoItemId: NodeInfoId): string =
     if self.node.wakuMix.isNil():
       return ""
     return self.node.wakuMix.pubKey.to0xHex()
+  of NodeInfoId.MaxMessageSize:
+    ## Configured max message size (in bytes) for this node.
+    return $self.conf.maxMessageSizeBytes
   else:
     return "unknown info item id"
 
-proc init*(T: typedesc[WakuStateInfo], node: WakuNode): T =
-  return WakuStateInfo(node: node)
+proc init*(T: typedesc[WakuStateInfo], node: WakuNode, conf: WakuConf): T =
+  return WakuStateInfo(node: node, conf: conf)

logos_delivery/waku/waku.nim

@@ -234,7 +234,7 @@ proc new*(
     return err("Failed setting up app callbacks: " & $error)
 
   var waku = Waku(
-    stateInfo: WakuStateInfo.init(node),
+    stateInfo: WakuStateInfo.init(node, wakuConf),
     conf: wakuConf,
     rng: rng,
     key: wakuConf.nodeKey,

tests/node/test_wakunode_health_monitor.nim

@@ -234,7 +234,9 @@ suite "Health Monitor - events":
     # `waku.node` is read on the messaging path; `conf`/`stateInfo` are supplied
     # solely to satisfy Waku's {.requiresInit.} fields.
     let waku = Waku(
-      node: nodeA, conf: defaultTestWakuConf(), stateInfo: WakuStateInfo.init(nodeA)
+      node: nodeA,
+      conf: defaultTestWakuConf(),
+      stateInfo: WakuStateInfo.init(nodeA, defaultTestWakuConf()),
     )
     let ds = MessagingClient
       .new(MessagingClientConf(reliabilityEnabled: Opt.some(false)), waku)
@@ -345,7 +347,9 @@ suite "Health Monitor - events":
     # `waku.node` is read on the messaging path; `conf`/`stateInfo` are supplied
     # solely to satisfy Waku's {.requiresInit.} fields.
     let waku = Waku(
-      node: nodeA, conf: defaultTestWakuConf(), stateInfo: WakuStateInfo.init(nodeA)
+      node: nodeA,
+      conf: defaultTestWakuConf(),
+      stateInfo: WakuStateInfo.init(nodeA, defaultTestWakuConf()),
     )
     let ds = MessagingClient
       .new(MessagingClientConf(reliabilityEnabled: Opt.some(false)), waku)

tests/wakunode2/test_app.nim

@@ -26,6 +26,20 @@ suite "Wakunode2 - Waku":
     check:
       version == git_version
 
+  test "max message size should be reported from node info":
+    ## Given
+    let conf = defaultTestWakuConf()
+
+    let waku = (waitFor Waku.new(conf)).valueOr:
+      raiseAssert error
+
+    ## When
+    let maxMessageSize = waku.stateInfo.getNodeInfoItem(NodeInfoId.MaxMessageSize)
+
+    ## Then
+    check:
+      maxMessageSize == $conf.maxMessageSizeBytes
+
 suite "Wakunode2 - Waku initialization":
   test "peer persistence setup should be successfully mounted":
     ## Given